Marine Annelid Research Articles

Carbon Monoxide Affinity of Chlorocruorin and Hæmoglobin

CHLOROCRUORIN, the green-red respiratory blood pigment of certain marine annelid worms, is the only known substance built on the same plan as haemoglobin. Like most kinds of haemoglobin, chlorocruorin has a higher affinity for carbon monoxide than for oxygen1. This property, valueless to animals, is utilized in experimental work to eliminate the possible respiratory activity of these pigments and so to test their functional significance2,3. The relative affinity of chlorocruorin (Ch), or of haemoglobin, for the two gases in the reversible reaction is given by the equilibrium constant K in the equation , from which it is seen that when the pigment is 50 per cent in the carboxy state and 50 per cent in the oxy state, K becomes the ratio of oxygen to carbon monoxide.

GLUCOSE CONTENT OF THE BODY FLUID IN MARINE ANNELIDS

GLUCOSE CONTENT OF THE BODY FLUID IN MARINE ANNELIDS

A COMPARATIVE STUDY OF THE LIPIDS IN SOME MARINE ANNELIDS

1. The amount of cholesterol, fatty acid, and phospholipid in various marine annelids was estimated.2. It was found that worms with a high content of cholesterol have also large amounts of phospholipid and fatty acid.

Periodic Spawning of ‘Palolo’ Worms in Pacific Waters

THE Mbalolo, Eunice viridia, is a marine annelid found in several places in islands of the Western Pacific. In Fiji I know of two and have heard of a third place in which the periodic ‘rising’ takes place. One such spot is between the shore and the fringing reef at the village of Tokou, in the island of Ovalau.

The identity of some marine annelid worms in the United States National Museum

The identity of some marine annelid worms in the United States National Museum

ON THE ABILITY OF CERTAIN MARINE INVERTEBRATES TO LIVE IN DILUTED SEA WATER

The ability of Limulus, Phascolosoma, and eighteen marine annelids to survive in various dilutions of sea water was studied. Most of the animals lived for a week or two in a mixture of three fourths sea water and one fourth fresh; several species lived in one half sea water. Limulus, Laonice, and Nereis lived and were active for periods of two to three weeks in one fourth sea water, but died in weaker solutions.

A new marine annelid from Chile

A new marine annelid from Chile

Tubular Cavities in Sarsens

WITH regard to Mr. F. Chapman's letter on the probable aeolian origin of sarsen rock (NATURE, August 18, p. 239), and his reference therein to my previous note, may I say that I was not referring to the holes so frequently present in the blocks—which I was told, when a student at the Royal School of Mines, some forty years ago, might be due to the presence of roots and rootlets in the sand before consolidation—but to a special case in which all the details suggested, from my previous knowledge of such things, the work of marine or esturine annelids. Without having seen what I saw, Mr. Chapman questions the validity of the grounds for the suggestion.

(1) A Monograph of the British Marine Annelids

THE volumes under notice constitute the last two parts of “A Monograph of the British Marine Annelids.” The Council of the Ray Society in the preface to the final volume, issued with the last part, “believe that they are interpreting the feelings of the members of the Society in offering to their President congratulations on the completion of this monograph, of which the first part was published no less than half a century ago.” This is an expression in which all zoologists would wish to join, and rejoice that Prof.

Probable Aeolian Origin of Greywether Sandstone

ON reading Mr. C. Carus-Wilson's note (NATURE, March 3, p. 292) referring to the long tubular holes seen in sarsen stones, which he says suggest “the work of marine annelids, anterior to the consolidation of the rock,” it struck me that some important light may be thrown on this subject by observations made on this side of the globe. First of all one might suggest that if these were annelid burrows they would have an average diameter, and there seems to be no evidence that the greywether sandstone, with its once softer siliceous matrix, was of marine origin. In Australia we have a great extent of country along the coast and inland, covered with dune formation, and these deposits enclose enormous quantities of vegetation. Plants that are growing on or near these dune areas, sometimes under swampy conditions, are covered over with sand, which is being blown about the stems of such grasses, reeds, and shrubs so as to completely enclose them. When the dune rock, some of which dates back to the early Pleistocene, has consolidated, a fracture reveals tubular holes which might suggest worms, but from their positions, at all angles, as well as vertical, and from their varied diameter and outline, are easily traced back to plant origin.

A Monograph of the British Marine Annelids

A Monograph of the British Marine Annelids

FURTHER EXPERIMENTS ON THE METHODS OF EGG-LAYING IN AMPHITRITE

On excursions, taken in connection with the course offered to students studying invertebrate zoology at Woods Hole, I have been impressed with the large number of forms not used for investigation. I believe this must be because little is known of theirlife-history and habits,becausemany of them arefairly abundant. With this idea in view, I recorded in a recent paper (†09)the results of some observations made upon the egg-laying habitsof one of the marine annelids. In the form studied, Amphiiriie, the germ cells arise in the typical way, i. e., from the coelomicepithelium.Very earlythese dehisceintothe body cavity and mix with the coelomic corpuscles. In some annelids as Nereis, the eggs escape by a rupture of the body wall. In Amphitriie, however, they pass to the exterior through certain nephridia that are highly modified to form gonaducts. In the paper mentioned above itwas shown that Amphiiriiedeposit. eggs at recurring periods that bear a close relation to the time of spring tides. It was further shown that at the time of ovi position, the body cavity contains floating free, not only the mature eggs and corpuscles but also the younger eggs in various stages of development. A single period of egg-laying occupies from 30—60 minutes, and most all eggs when extruded are in the metaphase of the firstpolarspindle.A few large,though unripe,eggs always escape especiallytoward the latterpart oftheperiod. In Fig.i isshown thecomparativesizeand shape of variousbodiesfound in the co@lomeat thistime. Itwillbe noticedthattheeggswhen first setfreeinthecoelomearesmaller than the red blood cells, yet neither cells nor eggs of this size ever escape during oviposition. Indeed, comparatively few of the largeunripe eggs pass out through the nephridia. The

Evidence that the primary change in stimulation is an increase in the permeability of the limiting membranes of the irritable elements

Various facts and theoretical considerations indicate clearly that the process of stimulation in muscle or nerve has its seat at the semi-permeable boundary layers or plasma membranes of the irritable elements, and consists in a sudden and reversible increase in the permeability of these membranes. After a brief review of this general evidence the following experiments were described. I. Experiments with the Larvœ of Arenicola cristata.—These are the free-swimming ciliated larvæ of a marine annelid; they are small worm-like organisms about 0.3 mm. in length, readily obtained in large quantity by rearing. The larvæ have a well-developed muscular system; the special peculiarity which fits them for the purpose of the following experiments is the presence throughout the whole body of a water-soluble yellow pigment; this substance is contained within the cells, and does not visibly leave the latter except under conditions of markedly increased permeability—as on death or after treatment with cytolytic substances (e. g., saponin); it then diffuses into the medium and, if sufficient larvæ are present, colors the latter a bright straw yellow. Its exit thus serves as a convenient index of increased permeability. It was found that during strong chemical stimulation a rapid loss of pigment always occurs: the rate and degree of this loss run closely parallel with the intensity of the stimulating action, as indicated by the extent and duration of the muscular shortening. Pure isotonic (m/2) solutions of neutral sodium salts (NaCOOCH3, NaCl, NaBr, NaN03, NaCl03, NaI, NaCNS) all cause strong and persistent muscular contraction accompanied by rapid loss of pigment; the addition of a little calcium chloride to the solution (I C.C. m/2 CaCl2 to 25 C.C. m/2 sodium salt) prevents both the stimulating action and the loss of pigment.

The early development of marine annelids

The early development of marine annelids

Preliminary Notice of a New Branchiate Oligochæte

THE term “Annélides abranches sétigères,” applied by Cuvier to the group which included the terrestrial and fresh-water Annelids, now known as the Oligochæta, is no longer applicable to that group. Several Oligochæta have been described as possessing gills, which, though for the most part differing in structure from the gills of the Polychæta, must be branchial in function. The most remarkable instance hitherto known is Alma nilotica, lately redescribed by Levinsen (Vidensk. Meddel. naturh. For. Kjöbnhavn, 1889) under the name of Digitibranchus niloticus. The posterior segments of this Annelid possess four to five branchial processes on each side of the dorsal middle line of the body. It cannot yet be regarded as an absolute certainty that this species belongs to the Oligochæta at all; but in any case processes of the body-wall, containing each a capillary loop, and therefore probably branchial in function, have been recently described by Prof. A. G. Bourne (Quart. Journ. Micr. Sci., vol. xxxi.) in a new genus of Naids—Chætobranchus. These processes, though doubtless branchial in function, are rather suggestive of the parapodia of marine Annelids, since they inclose, partially or entirely, the dorsal setæ. I have lately had the opportunity of examining this Annelid, through the kindness of Mr. Sowerby. The “Victoria regia tank” at the Botanical Society's Gardens, which produced the celebrated “Fresh-water Medusa” and other remarkable forms, furnished me with Chætobranchus, and with a new and interesting form of branchiate Oligochæte, which I propose to call Branchiura Sowerbii.

Societies and Academies

Societies and Academies

3. On the Arrangement and Relations of the Great Nerve-Cords in the Marine Annelids

FAM. EUPHROSYNIDÆ.—In Euphrosyne foliosa, Aud. and Ed., the separate nerve-cords are comparatively large, and lie quite within the body-wall, the oblique muscles, which generally bound the longitudinal ventral muscles, decussating beneath them.AMPHINOMIDÆ.—The cords are somewhat small and flattened in Chloeia, and occupy an area bounded internally by a transverse band of fibres, and externally by the circular muscular layer and the hypodermic basement-tissue. The oblique muscles are attached at the outer border of each trunk.

XII.–On some Points in the Structure of Tubifex

At least two species of Tubifex are abundant in Scotland, one of which is, perhaps, more prevalent in streams, the other in lakes. The former is common at the margin of the river Tay, when the water is low, in sandy tubes of little tenacity, and often in tunnels formed amongst the wet sand under stones, just as many of the marine annelids occur. Its length varies from three-fourths of an inch to an inch and a-half when stretched, and the segments range from fifty to seventy, the average number probably being sixty. The body is of various shades of dull fawn or pale madder-brown, somewhat interrupted by the pale bands at the junctions of the segments, and streaked by the reddish dorsal vessel; or, in summer, marked anteriorly by the whitish mass of the reproductive organs. It is easily recognised amongst its fellows by its faintly purplish or lilac hue, as well as by its peculiar mode of progression; and not a few are observed with reproducing heads and tails. This form, perhaps, has most claim to be called Tubifex rivulorum.