INYEKTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 457 



tain species have been found in Crustacea, others in niollnsks, &c. JMr. 

 A. Agassiz has briefly described, but not named, a remarkable worm 

 that he found very common in the jelly-lish, MnemioimH Leidiji, and the 

 young- of this or a difterent species was observed by me in the same Aca- 

 leph. It appeared to be a species of Scolex. It was pale purple, with 

 light yellowish orange stripes. I have previously mentioned a round 

 worm {Ascarisf) which frequently occurs in winter in one of our si)ecies 

 of Sagifta. 



Most of the species that, in the adult state, inhabit fishes, live while 

 young, or in the larval stages, in smaller fishes, or in other animals, 

 upon which the larger fishes feed, and from which they thus derive their 

 parasites. 



Besides the parasitic worms there are also many internal parasites that 

 belong to the Protozoa. 



The external parasites of fishes are also numerous. They are chiefly 

 Crustacea and leeches. 



Among the Crustacea there are a few species of Amphipods that are 

 parasitic. One of these, Laphystins sturionis, lives upon the gills of 

 fishes and upon the surface of the body. It was found on the gills of 

 the " goose-fish," [LopMus,) in Vineyard Sound, and on the back of 

 skates at Eastport. It is remarkable in having large claws developed 

 on the third and fourth i^airs of legs, those of the first and second be- 

 ing small. Its color is light red. 



Certain Isopod Crustacea, belonging to the genus Livoneea (Plate VI 

 fig. 29) and allied genera, live in the mouths and on the gills of fishes, 

 clinging firmly to the membrane of the roof of the month, or other 

 parts, by means of their strong sharp claws. These are generally 

 unsymmetrical inform. The species of the genus Bopyrus live on the 

 gills, under the carapax of shrimp and other Crustacea, producing large 

 tumors. A species is common on species of Rippolyie in the Bay of 

 Pundy : and a species has been found in this region. The genus Cepon 

 is allied to the last, and our species occurs uiuler the carapax of the 

 "fiddler-crabs" in this region. 



Among the Eutomostraca the number of parasitic species is still 

 greater, but most of these live on the external surface and gills of fishes, 

 though some of them occur also in the mouth. The species of Panda- 

 rus and allied genera adhere firmly to the skin, and are provided with a 

 proboscis. They are very common on sharks, but occur also on other 

 fishes. A Pavdorfi^ t e VII, fig. 31) and Nogagus LatreiUil (Plate 

 VII, fig. 32) were both f )iiiid on " Atwood's shark," the " man-eater" of 

 this region, associated also with Nogagus tenax. The species of '•'■N'oga- 

 gits^^ are merely the males of other genera, for no one has yet deter- 

 mined both males and females of the various species. The young of 

 one species, CaUgiis rapax, were found swimming free at the surface. 



The species of Argulns and allied genera are less strictly parasitic, or 

 rfither they adhere less closely, and apparently leave the fishes at pleas- 



