Cymatogaster Research Articles

Helminth Parasites of Embiotocid Fishes. I. A New Genus of the Trematode Family Zoogonidae

The parasitic fauna of the viviparous perches of the family Embiotocidae is not well known. The parasites reported in the available literature from hosts of this family are Genitocotyle acirrata Park, Telolecithus pugetensis Lloyd and Guberlet, and Postmonorchis donacis Young. The first named was described by Park (1937) from Holconotus rhodoterus Agassiz taken at Dillon Beach, California and also by Manter and Van Cleave (1951) from Damalichthys vacca Girard taken at La Jolla, California. Lloyd and Guberlet (1932) described T. pugetensis from Cymatogaster aggregata Gibbons taken in Puget Sound, Washington. P. donacis was described by Young (1953) from Micrometrus (undoubtedly M. minimus (Gibbons)), C!ymatogaster (undoubtedly C. aggregata Gibbons), and from Embiotoca jacksoni Agassiz; all taken from Mission Bay, Calif. From one of the species of this family occurring in Japan, Ditrema temmincki Bleeker, Yamaguti (1934; 1939; 1942) has described Decemtestis ditremiatis Yamaguti, Stephanostomum ditrematis (Yamaguti, 1939) Manter, 1947, and Opegaster ditrematis Yamaguti. From the same host, Ozaki (1929) described Coitocaecum latum Ozaki. Haderlie (1953) mentions the absence of helminth parasites in a single specimen of Hysterocarpus traski Gibbons (the only fresh-water embiotocid). This dearth of information is certainly not due to the rarity of the embiotocids. At least nineteen species of this family are well known components of the fish fauna of the California coast (Tarp, 1952). A preliminary survey indicated that these fishes harbor a number of helminth parasites. A detailed parasitological study of these forms has been undertaken in hope of obtaining information which may aid in further understanding the taxonomy and ecology of the embiotocids by determination of apparent host specificity, as well as contributing to our knowledge of the helminth fauna of the Pacific. During the examination of specimens of Embiotoca jacksoni Agassiz taken at Newport Bay and Morro Bay, California, 18 of 26 fishes examined harbored a trematode species belonging to the family Zoogonidae Odhner, 1911. A detailed study revealed that this form cannot be referred to any genus of that family, and it is concluded that the erection of a new genus is required. Appreciation is expressed to Dr. Clark P. Read and to Dr. Boyd W. Walker with whose guidance and assistance this work was carried out.

THE AGGLUTINATION OF FISH ERYTHROCYTES BY NORMAL HUMAN SERA

1. Normal human sera were found to agglutinate the erythrocytes of the shiner sea-perch (Cymatogaster aggregata) and of the kingfish (Genyonemus lineatus).2. Agglutination was shown to occur by virtue of four different antigens, each species having two of these four in its erythrocytes.3. Of these, Genyonemus had an antigen with a specificity closely resembling the human B substance (designated here as F-1) and a species-specific antigen (F-2) peculiar to itself.4. Cymatogaster had a species-specific antigen (F-3) and an antigen with a specificity resembling that of the Forssman antigen (F-4).5. No individual variations were found in either fish with respect to these antigens.

An Accessory Respiratory Device in Embryos of the Embiotocid Fish, Cymatogaster aggregata, during Gestation

sively from the fluid of the ovarian cavity of the mother. Secretions from the cells lining the maternal ovarian cavity, and also fluid from the swollen ovary, contribute to the nutritive supply. The fluid is fortified also (Turner, 1938) by epithelial cells desquamated from the internal lining of the ovarian cavity and also by the remains of dead and partially absorbed embryos. The ovarian liquor enters the alimentary canals of the embryos by way of the mouths or opercular openings, and nutritive materials are absorbed from it by the intestine which is modified for the purpose. Nitrogenous wastes and partially dehydrated residues from the alimentary canals of the embryos are discharged into the ovarian cavity in which the embryos are retained and live. Presumably the toxic compounds are absorbed through the vascular ovarian tissues of the mother and are eliminated by the maternal excretory organs. The respiratory requirements of the early embryos are not great and apparently are met by the vascular portal system covering the body wall of the pericardial and peritoneal cavities. These portal systems are bathed by the maternal ovarian fluid. During later stages of development, there is an opportunity for exchange of oxygen and carbon dioxide between the gills of the embryo and the ovarian fluid as the fluid is drawn into the alimentary canal through the pharynx. Structures adapted for respiratory exchange are developed in the older embryos and appear as spatulate vascular expansions of the tissue at the margins of the dorsal and anal fins. These structures are lost near the close of the gestation period. An undescribed structural feature which facilitates respiration has been discovered in embryos ready for birth and is described in the following paragraph. At the close of the period of gestation the embryos are closely packed within the ovarian cavity of the mother and are in contact with the ovarian walls or the ovarian ovigerous lamellae. In approximately one-half of the embryos, the opercular opening on one side has been invaded by a fold of tissue from the wall or one of the septa of the ovary to a depth of about 2 mm,