476 EEPOET OF COMMISSIONER OF FISH AND FISHERIES. 



tbat all the individuals may have been brought from the south, in the 

 spring, when quite small, attached to the oysters. It may be, however, 

 that it has really become naturalized on our shores. It is very common 

 in the Gulf of Mexico, and on other parts of the southern coast. The 

 Anomia glabra (p. 311, Plate XXII, figs. 241, 242, 242a) is also very 

 commonly found adhering to oysters. 



The hard sandy tubes of Sabellaria vulgaris (p. 321, Plate XVII, figs 

 88, 88a) and the calcareous tubes of Serpula dianthus (p. 322) are very fre- 

 quent upon oyster-shells, and occasionally those of Potamilla oculifera, 

 (p 322, Plate XVII, fig. 86,) Scionopsis palmata, (p. 321,) and other species 

 are met with. Many other Annelids are to be found burrowing or hiding 

 beneath the oysters. The common green star-fish, Asterias arenicola, (p. 

 326, Plate XXX Y, fig. 269,) occasionally occurs on the oyster-beds near 

 the mouths of estuaries, but is seldom sufficiently abundant in the 

 brackish waters to do serious damage to the oyster-beds. 



In the brackish waters the " drill," Urosalpinx cinerea, (p. 306, Plate 

 XXI, fig. 116,) is the worst enemy of the oyster, and is sometimes so 

 numerous as to do very serious damage. 



Several species of Hydroids grow adhering to oysters. The most 

 abundant of these, in brackish water, is usually Halecium gracile V., 

 {p. 328,) but two or three species of Obelia and some other forms occur. 



Of Bryozoa, one of the most common species is the Escharella variab- 

 ilis, (p. 312, Plate XXXIII, fig. 256,) which forms calcareous incrusta- 

 tions. The Bugula turrita, (p. 311, Plate XXXIV, figs 258, 259,) and 

 Vesicularia dicliotoma V. (p. 404) are also common. The Alcyonidium 

 kirsutum, (p. 404,) which forms soft fleshy crusts over the surface of 

 the shells, is quite frequently seen. 



The common red sponge (p. 330) is often abundant on the oyster-beds 

 where the water is not much freshened. 



List of species inhabiting oyster-beds in brackish waters. 



ARTICULATA. 



Chironomus oceanicus. 



Insects. 



Page. 

 379 



Crustacea. 



Page. 



Pinnotheres ostreum 367 



Cancer irroratus 312 



Panopeus Herbstii 472 



P. Sayi 312 



P. depressus 312 



Carcinus granulatus 312 



Libinia canaliculata 368 



Eupagnrus pollicaris 313 



Page. 



E. longicarpus 313 



Crangon vulgaris 339 



Mysis Americana 370 



Melita nitida 314 



Ampelisca, sp 431 



Unciola irrorata 340 



Corophium cylindricum 370 



Epelys trilobus 370 



