Phyllopod Crustacean Research Articles

Early Palaeozoic Discinocarina: a key to the appearance of cephalopod jaws

Cephalopoda is the only class of molluscs in which virtually all its modern representatives have a pair of powerful jaws. There is little doubt that jaws have contributed to the evolutionary success of cephalopods, but their origin still remains a mystery. Though cephalopods appeared at the end of the Cambrian, the oldest unequivocal jaws have been reported to date from the Late Devonian, though they were initially interpreted as phyllopod crustaceans of the suborder Discinocarina. After their relation with ammonoids was proven, they were considered as opercula, and only later their mandibular nature was recognized and widely accepted. Finds of discinocarins from Silurian deposits are still considered as opercula of ammonoid ancestors - nautiloids of the order Orthocerida. However, according to modern ideas, there is no place within their soft body for the location of such large opercula. Moreover, the repeated appearance of very similar structures in the same evolutionary line at least twice, but in different places of the body and for different purposes seems highly improbable. A new hypothesis is proposed herein, in which the Silurian fossils, earlier assigned to Discinocarina, are not specialized opercula, but protective shields, to defend orthocerids not from the predators, but from their own prey. The chitinous plates around the mouth likely appeared in the Silurian orthocerids for protection from such damage and later, during Silurian and Devonian, most likely gradually evolved into the jaws.

Late Devonian (Frasnian) phyllopod and phyllocarid crustacean shields from Belgium reinterpreted as ammonoid anaptychi.

The taxonomic affinities of fossils from the Frasnian succession of Belgium previously described as phyllopod and phyllocarid crustacean shields are discussed. The rediscovery of the holotype of Ellipsocaris dewalquei, the type species of the genus Ellipsocaris Woodward in Dewalque, 1882, allows to end the discussion on the taxonomic assignation of the genus Ellipsocaris. It is removed from the phyllopod crustaceans as interpreted originally and considered here as an ammonoid anaptychus. Furthermore, it is considered to be a junior synonym of the genus Sidetes Giebel, 1847. Similarly, Van Straelen's (1933) lower to middle Frasnian record Spathiocaris chagrinensis Ruedemann, 1916, is also an ammonoid anaptychus. Although ammonoids can be relatively frequent in some Frasnian horizons of Belgium, anaptychi remain particularly scarce and the attribution to the present material to peculiar ammonoid species is not possible.

Aquatic Invertebrate Communities of Perennial Pans in Mpumalanga, South Africa: A Diversity and Functional Approach

Perennial pans are a common feature of the Mpumalanga Highveld in South Africa and are increasingly under threat from mining and agricultural activities. Pans are endorheic wetlands that can be perennial or ephemeral in nature. They are widespread in arid and semi-arid regions throughout the world. Although phyllopod crustaceans dominate pan communities in arid regions, the invertebrate communities of perenni al pans have not been well studied. The aim of the current research was to characterise the invertebrate com munities of several pans (both natural and impaired). A combination of taxonomic and functional approaches was followed to study these communities. The macroinvertebrate species diversity of the pans was comparable to similar ecosystems in southern Africa and other parts of the world. Results indicate large spatial and temporal variations in diversity. This variation became less obvious when the analysis was based on biological traits. It was also evident that both coal mining and agricultural activities had an impact on the aquatic invertebrate community structures. These changes were apparent in both the diversity and the biological traits of the invertebrate communities of adjacent pans.

Ecology of four turbid clay pans during a filling-drying cycle in the Paroo, semi-arid Australia

The clay pans studied were small (<2 ha), shallow (<30 cm) and contained very turbid, alkaline water of low conductivity for 40–90 days. Nutrients peaked early but chlorophyll-a values varied through time. Water temperatures ranged from 3.5 to 25.5 °C. Cumulative species richness ranged from 30 to 55, with mean momentary species richness varying from 15.5 to 29.1 among the four pans. Macroinvertebrate assemblages were dominated by adult phyllopods, hemipterans and coleopterans, and zooplankton was dominated by juvenile phyllopods, copepods and cladocerans. No macrophytes were present. Ordination showed two pairs of pans (A+B and C+D) which matched ordination of physicochemical data, with turbidity the factor best explaining the pattern. Macroinvertebrate assemblages varied between the centre and littoral zone of all pans, particularly in C and D in which CPOM was more abundant in the littoral. Grouping of assemblages was directed as much by differences in abundance as variation in species composition. Succession was directional and continuous. Among macroinvertebrates, insects dominated initially and terminally, but phyllopod crustaceans were important much of the time. In the zooplankton, phyllopods dominated initially then entomostracans, with final assemblages mostly consisting of copepods. Succession was quicker and later assemblages more stable in zooplankton. The feeding group of filter feeders/collectors dominated during the life of the pans, except at the beginning and end when predators were important. The major carbon source was algal, despite the high turbidity and abundant detrital matter.

Whither Anomalocaris? The search in the Burgess Shale continues

A hundred years ago, Anomalocaris canadensis Whiteaves, 1892, was described as the body of a Phyllopod Crustacean. At NAPC III in Montreal in 1982, Whittington and Briggs showed that Anomalocaris canadensis was a claw, one of a pair at the front of an extraordinary predatory animal, whose jaws had previously been described as a jellyfish (Peytoia). The search to understand Anomalocaris and its relatives continues. So does the mistaken allocation of separated parts.In 1991, the first complete Anomalocaris canadensis was collected. It has a fan tail, much like the tail of another Burgess Shale conundrum, Opabinia. Another new specimen shows that its head and claws were more flexible than previously realized, and its eyes were on stalks.The large feeding claw, Appendage F, was allocated first to the arthropod, Sidneyia, by Walcott, then to the other Anomalocaris species, A. nathorsti, by Whittington and Briggs. The small size and lack of strong cross spines on the claws of A. nathorsti suggest that Appendage F probably came from another anomalocarid. Another puzzling feature on A. nathorsti is the thin, segmented structure running across the abdomen, one per body segment, ending in a club-shaped extremity on each side.A third anomalocarid is now recognized in the Burgess Shale. Its front half is composed of 3 or 4 carapace like parts previously named Hurdia and Proboscicaris. Two small sheathed claws on stalks are attached at the rear of the “carapaces”. Hanging below the rear of the “carapaces” is a grasping, feeding organ composed of a pair of claws and Peytoia jaws with an inner set of teeth. It is connected to the body which has 11 segments and a tail. The two “oblique compressions” and the Peytoia jaws with the extra group of “spines” within the mouth allocated by Whittington and Briggs (1985) to Anomalocaris nathorsti almost certainly belong to the Hurdia anomalocarid.It is evident that attempting to allocate anomalocarid parts to a particular anomalocarid is much like a Pin-the-Tail-on-the-Donkey game. In both cases the players are operating in the dark. The differences are that there is an unknown number of anomalocarids in the Burgess Shale and not only do they disarticulate easily, but they often have similar parts. As a consequence, our understanding of the anomalocarids is almost completely dependent on finding articulated specimens with the parts in place. This in turn depends on the success of field excavation. It took 100 years and 12 seasons of excavation to get the first complete Anomalocaris canadensis.

Egg envelopes of Streptocephalus dichotomus Baird: A structural and histochemical study

The origin, ultrastructure and histochemical properties of the egg membranes in the South Indian anostracan, Streptocephalus dichotomus have been studied. The egg morphology and the ultrastructure of the tertiary membrane of this phyllopod crustacean have been examined both by scanning and transmission electron microscopy. Scanning electron microscopic observations on the egg surface reveal the characteristic ridges on the egg surface with pores. Similarly, the tertiary egg shell of S. dichotomus consists of two distinct layers, an outer cortex and an inner alveolar layer. There are specific differences in the structure and in the relationship of one layer to the other. The alveolar layer is characterised by large lipid droplets and an alveolar mesh. These two layers termed as tertiary layers are secreted by maternal shell glands. The outer tertiary egg layers are phenolically tanned, the precursor materials for tanning being derived from shell gland secretions.

A New Conchostracan Phyllopod, Eulimnadia alineata, from Arkansas

Early in 1949, Dr. Fenner A. Chace, Jr., Curator of Marine Invertebrates, U. S. National Msueum, sent nine specimens of a phyllopod crustacean to the writer for identification. These specimens had been collected during August, 1948 in rice fields near Stuttgart, Arkansas by Prof. F. E. Whitehead of the University of Arkansas. Upon preliminary examination the animals were seen to belong to the conchostracan genus Eulimnadia and seemed to represent an undescribed species. However, the single male, essential in diagnosis of species in the genus, was immature thus making positive identification uncertain. A subsequent collection on June 30, 1949, from the same locality, by the same collector, contained mature males thus makinlg possible a more certain evaluation of the animals. It has been determined that these are quite distinctive and represent a new species of the genus. The name, Eulimnadia alineata, is here proposed for this species.

A new species of phyllopod crustacean from the southwestern short-grass prairies

A new species of phyllopod crustacean from the southwestern short-grass prairies

Societies and Academies

PARIS Academy of Sciences, July 23 (CM., 199, 249-328).—CH. POBCHEB, HENBI VOLKBINGEB and MLLE. JEANNE BBIGANDO: Contribution to the study of casein. Detailed study of the absorption spectra, of casein and paracasein. EDOUARD CHATTON and MLLE. BERTHE BIECHELER: The Coccidinidae, dino-flagellate coccidiomorph parasites of Dinoflagellates and the phylum of the Phytodinozoa. MARC KRASNER: The first case of Fermat's theorem. A. GELFOND:—Some new results in the theory of transcendental numbers. JEAN MASCART: The perihelia of the minor planets. HENRI MINEUR and HENRI CAMICHEL: The variations of the ellipsoid of velocities in the galactic plane. HANS EKSTEIN and MICHEL MAGAT: Remarks on the forces of Van der Waals in liquid mercury and in the molecule Hg2. GEORGES DECHENE: The Johnsen-Rabbeck effect. The author gives a new explanation of this phenomenon which also affords an explanation of an experiment described by Toby. DANIEL BODBOUX and RENE RIVAULT: Some attempts to photograph the television emissions from London and a local station on short waves. Description of the apparatus used for the reception with reproductions of the photographs obtained. ANTOINE GOLDET and ARCADIUS PIEKARA: The thermal variation of the magnetic double refraction of mixtures. The case of a mixture presenting a critical point. L. COLOM-BIER: The electrolytic potential of nickel. Values varying between 0-138 and 0-621 have been published for this constant. The author discusses the possible causes of this variation and describes experiments in which the errors due to gases fixed on the surface of the nickel and to the increase of activity due to the presence of hydrogen are eliminated as far as possible. The values found fall between? 0-225 and 0-23. ANTOINE MARSAT: The modes of graphical representation of the distribution of the flux emitted by a light source. JEAN PAUL MATHIEU: The optical activity and solubility of some cobaltammines. PRIVAULT: Weak lines of the K series of the elements from chromium to copper. The fluorescence lines of some compounds of these elements. F. HAMMEL:—The X-ray spectra of manganese sulphate and its hydrates. Five specimens of the monohydrate of manganese sulphate prepared in different ways give the same spectrum: nothing in the spectra of the five specimens suggests a difference of structure. These results are not in agreement with those of Krepelka and Rejha. I. ZLOTOWSKI: The heat of the y-radiation of radium. An application of the adiabatic microcalorimeter of Swietoslawski and Dorabialska. MARITJS BBIAND, PAUL DUMANOIS and PAUL LAFFITTE: The influence of temperature on the limits of inflammability of some combustible vapours either pure or in admixture. Data are given for isopentane, acetone, methyl, ethyl and butyl alcohols and some binary and ternary mixtures. MME. ALMA DOBBY: The osmotic pressure of polymerised substances. Utilising an apparatus capable of measuring with sufficient accuracy osmotic pressures down to 1-5 mm. of water, the limiting value of the ratio pressure to concentration can be determined. These limiting values are independent of the solvent. The molecular weight of nitrocellulose thus obtained is 110,000. MABCEL CHATELET: Some reactions of divalent chromium chloride. Compounds of chromous chloride with pyridine and with ammonia. HENBI VOLKBINGEB, ABAKEL TCHAKIBIAN and MME. MABIE FBEYMANN: The Raman spectra of the metallochloroforms in relation with their structure. Comparison of the Raman spectra of chloroform, silicochloroform, germanochloroform and chlorstannic acid. The correspondences show that these four compounds have analogous structures. MLLE. BLANCHE GBEDY: The (Raman) spectra of some acetylene compounds of the cyclane series. LEON PALFBAY and MLLE. SUZANNE TALLABD: The influence of the free acidity on the determination of aldehydes and ketones by hydroxylamine hydrochloride. The amounts of aldehyde or ketone found by the hydroxylamine method are affected by the presence of organic acids, but this error can be minimised by the use of bromo-phenol blue as indicator. RENE EMILE BBEUIL: Complex compounds of ferrous salts with ethyl-enediamine and trimethylenediamine. CAM. LEFEVBE and CH. DESGBEZ: Contribution to the study of the aromatic sulphides. F. LINK: The illumination of the higher atmosphere and the twilight tables of Jean,Lugeon. J. LACOSTE and J. P. ROTHE: Earthquakes in France in 1930-33. ANDBE DATJPHINE: The mode of formation of the pecto-cellulosic membrane. P. MARTENS: New observations on the cuticle of floral epiderms. MATJBICE PIETTBE: Concerning the protein equilibrium of the blood serum. SEBASTIEN SABETAY and MME. HEBMINE SABETAY: A colour reaction of the azulenogen sesquiterpenes. A. LEPAPE and R. TBANNOY: The influence of radium on the cultural yields of some plants. J. E. ABELOUS and R. ABGAUD: The formation of adrenaline in the suprarenal capsule. Combined or virtual adrenaline and free adrenaline. PAUL MATHIAS and MME. MABGTJEBITE BOUAT: The development of the egg of Branchipus stagnalis, a phyllopod crustacean. MLLE. A, TETBY: Description of a French species of the genus Pelodrilus. W. KOPACZEWSKI: Seric lacto-gelification considered as an index of neoformation. LEON BINET and MLLE. MADELEINE BOCHET: An arrangement for artificial respiration in man.

Societies and Academies

PARIS. Academy of Sciences, July 28.—Deslandres: The raies ultimes of the alkalis and alkaline earths.—Bigourdan: The observatory of Courtanvaux at Colombes.—L. Blaringhem: The influence of the pollen on the movements which precede the opening of the flowers in poppies.—J. Costantin: The increase in resistance to disease (of plants) due to altitude. The resistance of cultivated plants to disease is increased when the plant is grown at a high altitude. The results with potato, sugar cane, and coffee plant are cited.—Ch. Gravier and P, Mathias: The reproduction of a phyllopod crustacean of the group Conchostriaceae (Cyzicus cycladoides).—Paul Pascal and Erling Botolfsen: The synthesis of methane starting with carbon monoxide and steam. In presence of a nickel catalyst, the reaction between carbon monoxide and steam depends upon the temperature. At 275° C. the reaction is 4 CO + 2H2O-3CO2 + CH4, but at 750° C and upwards the well-known reaction CO+H2O>COg + H2 occurs.—E. Mathias and G. Grenet: The daily variation of the electric field of the air at the observatory at the coast of Landais. The results agree with those obtained at the summit of the Puy de Dome and at Val Joyeux in showing daily two maxima and two minima of unequal importance. The amplitude of the daily variation is considerable at the lower station, the ratio of the maximum to the minimum being 3 for the summer, 2-1 for the spring.—Paul Delens: The geometry of connected cycles.—Jean Pierre Robert: Limited formulae of mediation.—S. Sonoda: Radiation resistance of a small antenna oscillating in half waves.—L. Brillouin: The electrons in metals and the role of the conditions of Bragg's selective reflection.—Jean Thibaud and F. Dupre La Tour: Study of the a and j8 crystals of the fatty acids.—J. J. Trillat and A. Nowakowski.: The orientation of the fatty acids in contact with a liquid phase. It is shown that using the method of the tangent drop, it i& possible to follow the various factors which govern the formation of crystals and the orientation of the molecules of fatty acids in contact with various liquids.—George I. Costeanu: Batteries with a sodium cathode.—Guy. Emschwilier: The absorption of ultra-violet light by the alkyl iodides. Details of quantitative measurements by the photographic method, using the recording microphotometer of Lambert and Chalonge. The substances studied included methyl, ethyl, propyl, butyl, isopropyl, isobutyl, secondary butyl, and tertiary butyl iodides and iodobenzene: these were examined as liquids and as gases.—Mile. L. Popovici: Naphthyl-j3-glyoxylie acid and some of its derivatives.—Albert Saint-Maxen: The autoxidation of hydroquinone. To a solution of hydroquinone, sodium hydroxide is gradually added. Curves are given showing the light absorbed, the electrical conductivity, and the oxidation velocity as functions of the amount of alkali added.—Ch. Courtot and V. Ouperoff: The systematic study of the condensation of the aromatic monoketones with the tertiary aromatic amines, under the action of aluminium chloride.—Jean Lugeon: Ionisation and electric field at El Golea: lightning visible at 800 kilometres: mirages seen from a motor car: condensations in the dunes of the Grand Erg.—Rene Girard and Robert Lemesle: Structural peculiarities of the floral axis of Ramondia pyrenaica.—Mile. Lucienne George: Some anatomical peculiarities of Gnetum.—Aug. Chevalier: The mycocecidia of the gyrophore of Arachis.—Fernand Mercier: A new water soluble derivative of camphor and of sparteine: sparteine camphosulphonate.—M. Javillier and Mile. L. Emerique: A method of purification of carotene and the vitamin activity of a purified carotene. A carotene purified by five repetitions of a process described, and melting at 185° (the melting point given by Drummond for his pure but physiologically inactive carotene), still possesses powerful vitamin properties.—Edm. Sergent and H. Ducros-Rougebief: The preservation in Nature during the winter of Droso-phila, carriers of yeasts.—A. Leulier and P. Sedaillan: The affinity of the diphtheria bacillus for copper. The diphtheria bacillus is not injured by small proportions of copper sulphate and fixes this metal in notable amount.—Charles Benoit and Andre Hel-bronner: Photochemical therapeutics.

The morphology of the frontal appendage of the male in the Phyllopod crustacean Thamnocephalus platyurus Packard

Journal of MorphologyVolume 26, Issue 4 p. 703-718 Article The morphology of the frontal appendage of the male in the Phyllopod crustacean Thamnocephalus platyurus Packard Arthur T. Evans, Arthur T. EvansSearch for more papers by this author Arthur T. Evans, Arthur T. EvansSearch for more papers by this author First published: December 1915 https://doi.org/10.1002/jmor.1050260404AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Volume26, Issue4December 1915Pages 703-718 RelatedInformation

XXXII. The Silurian Volcanic Rocks of the Southern Uplands of Scotland

Reference was made at the outset to the great development of volcanic rocks of Arenig age in the Southern Uplands, where they are brought to the surface along the crests of anticlinal folds. The largest area of these rocks now exposed at the surface occurs in the neighbourhood of Ballantrae, Ayrshire, where they consist of a succession of diabase and diabase-porphyrite lavas, tuffs and agglomerates. The age of these volcanic materials is clearly defined by fossiliferous flinty mudstones interstratified with the lavas, and by black graptolitic mudstones in the tuffs and agglomerates near the top. The organisms obtained from these deposits comprise graptolites of Middle Arenig age, and hingeless brachiopods, together with a phyllopod crustacean. The lavas, tuffs and agglomerates of Arenig age, are overlain in Ayrshire and throughout the Uplands by an important zone of radiolarian chert belonging partly to Arenig, and partly to Lower Llandeilo time. Thereafter the various intrusive igneous rocks associated with the volcanic series of Ballantrae were indicated, which include masses of serpentine, gabbro, epidiorite, dolerite and granite: their relations to each other in the field being in many places obscure. It was shown that towards the close of Llandeilo time the volcanic and plutonic rocks of the Ballantrae region, together with the overlying sediments, were elevated and exposed to denudation, the materials of the Kirkland and Benan conglomerates at the base of the Girvan series having been derived from these older rocks. Thereafter attention was directed to the numerous inliers of Arenig volcanic rocks

V.—On the Application of the Sand-Blast for the Development of Trilobites

My endeavours to establish a genetic relationship between the Annelida and the Phyllopod Crustacean Apus led me, very naturally, to the study of the Trilobites. Specimens were kindly lent me by Dr. Woodward, F.R.S., Prof. Judd, F.R.S., and by Prof. G. B. Howes, it being my privilege at the time to be working in the Huxley Research Laboratory, which is under his direction.Picking at the fossil with a steel point taught me, what every worker soon finds out for himself, that the limbs which, under such a dorsal shield, would probably have been thin-walled structures, could not be differentiated from the matrix by any such method. Was there, then, no mechanical method of revealing the undersurface? At first I thought, among other things, of a stream of water, mixed with emery powder, forced through a rose; this idea led, very naturally, to the sand-blast. a visit to the London Sandblast “Works” (58A, Gray's Inn Road) gave some promise. The proprietor was kind enough to express interest in the idea, and showed me blocks of granite which had been treated with the sand-blast, and in which the harder elements stood outingood relief. a very short application of one of the sand-blasts belonging to the Works to the under-surface of a Trilobite from the soft Wenloek cleared away a large portion of the matrix, and revealed a small area of the under-surface of the carapace completely cleaned.inthis specimen there was no trace of any under membrane having been cut through, and the carapace was probably the last remnant of a cast skin.

Note on the occurrence of a new species of Carboniferous Crustacean at Ardross, near Elie, Fife

At a meeting of this Society, held on the evening of the 21st February 1884, my friend Mr Kinnear and I exhibited a collection of Carboniferous Crustacea obtained from a series of beds of limestone shales which are exposed on the shore between tide-marks at Ardross Castle, near Elie, on the south coast of Fife. It was then stated, in a short notice of the fossils, that the Crustacean remains, although numerous, comprised only two species. One of these was a Phyllopod Crustacean, Dithyrocaris glabra, Eth., and the other a Decapod Crustacean, Palæocrangon socialis, Salter. So far as I am aware, these were the only species of Crustacea which had been detected in these beds at Ardross, until I was so fortunate as to come across a single specimen of the genus Acanthocaris, Peach. As far back as 1861, Crustacean remains had been noted in these beds by the Rev. Thomas Brown, whose admirable paper, ‶On the Mountain Limestone and Lower Carboniferous Rocks of the Fifeshire Coasts,″ was published in the ‶Transactions of the Royal Society of Edinburgh,″ vol. xxii. p. 385. There he mentions having obtained at Ardross specimens of Dithyrocaris and Palæocrangon. The former occurs as detached valves, but with no trace of the body segments, except the triply divided tail spine, of which two or three specimens have been obtained. The genus Acanthocaris, 1 belonging to the order Phyllopoda, was instituted by Mr B. N. Peach for the reception of certain forms of Carboniferous Crustacea which are nearly

III.—Note on Ellipsocaris Dewalquei, a new Phyllopod Crustacean Shield from the Upper Devonian of Belgium

The specimen which forms the subject of this note has been kindly placed in my hands by Professor G. Dewalque for examination, and is of extreme interest and importance to me in my researches upon the Fossil Crustacea. It is not, as was at first supposed, the metastome of Eurypterus or of Pterygotus; on the contrary, it represents an almost entire carapace of a new genus and species of Phyllopod Crustacean allied to Peltocaris

I.—On a Series of Phyllopod Crustacean Shields from the Upper Devonian of the Eifel; and on one from the Wenlock Shale of S. Wales

Having in the autumn of 1878 arranged to make a geological excursion to the Eifel, with my friend Mr. John Edward Lee, F.S.A., F.G.S., of Torquay, we were so fortunate, when near Gerolstein, to meet Professor Dr. Ferdinand Roemer, of the University of Breslau, Silesia, who has made the Eifel region his special study, and who cordially joined our party, giving us the benefit of his great knowledge of this most interesting geological region.

New Phyllopod crustaceans from the Devonian of western New York

New Phyllopod crustaceans from the Devonian of western New York

XXIX.—On the occurrence of a small and new Phyllopod Crustacean, referable to the genus Leaia, in the Lower Carboniferous rocks of the Edinburgh Neighbourhood

XXIX.—<i>On the occurrence of a small and new Phyllopod Crustacean, referable to the genus</i> Leaia, <i>in the Lower Carboniferous rocks of the Edinburgh Neighbourhood</i>

IV.—On some Fossils from the Lower Silurian Rocks of the South of Scotland

The Lower Silurian Rocks of the South of Scotland, below the level of the Wrae Limestone of Peeblesshire, though of great thickness, and little altered by igneous agency, have as yet yielded but few of the higher forms of animal life. Two species of a phyllopod crustacean, (Peltocaris aptychoides and P. Harknessi, Salter), were discovered by Prof. Harkness, along with the first Brachiopod found in these deposits, the Siphonotreta micula of McCoy. Another crustacean of an allied genus, described by Mr. Henry Woodward, and named by him Discinocaris Browniana, was discovered last year in the neighbourhood of Moffat, by Mr. D. J. Brown. Besides the above, there occur traces of the action of marine worms, and I have, in addition, found one, possibly two, species of Lingula, a thin-walled Orthoceras, or Pteropod, and some curious spine-like bodies, probably referable to crustaceans. With the exception of these scanty remains, the strata under consideration have yielded no fossils higher in the scale of existence than Graptolites. In no other British deposit do we, however, find a greater profusion of these beautiful and characteristic fossils, or a greater number of specific types. It is the object of this communication to describe certain new forms of Graptolites which have come under my notice, together with one remarkable genus, apparently allied to the Graptolitidœ, though probably representing a different order.

XXXVII. Exhibition of Peltocaris aptychoides from Moffat

A specimen of Peltocaris aptychoides, from the graptolite shales, lower Silurian beds, Moffat. He mentioned that it was the carapace of a small Phyllopod crustacean, fragments of which had occasionally been found in the Llandeilo flags of Dumfriesshire, and, from their resemblance to those found in the Carboniferous Limestone, Mr. Salter had named them provisionally Dithyrocaris aptychoides. On sending the cast of this specimen to Mr. Salter, he stated that it was the first perfect specimen he had seen, and, from its shield-like form, he re-named the genus Peltocaris. This 89-word extract was created in the absence of an abstract