INVERTEBRATE ANIMALS OF VINEYARD SOUND, ETC. 491 

 MOLLTJSCA. 



Gastropods. 



Page. 



Sycotypus canalieulatus 399 



Tritia trivittata 354 



Orepidula fornicata 355 



Page. 



C. unguiformis 354 



Lrmatia heros 490 



Neverita duplicata 490 



LamellibrancJis. 



Page. 



Ensatella Americana 490 



Siliqua costata c 426 



. Page. 



Mya arenaria 490 



Mactra solidissiina 490 



RADIATA. 



Ecliinoderms. 



Page. 

 Leptosynapta Girardii 490 



Page. 

 Echinarachnius parma 490 



IY. 3. — Animals inhabiting rocky bottoms off the open coast. 



The fauna of the rocky bottoms in these outer waters is rich and in- 

 teresting, and decidedly northern in character, though there is usually 

 an admixture with southern species. 



The principal localities where dredgings were made on this kind of 

 ground are : First, off Gay Head and Devil's Bridge, at localities marked 

 on the chart, 53, a, b, c, d; 55, a, b, c; 56, a, b, c, d; 57, «, b, c, d ; 58, 

 a, b, c ; 59, a, b, c; 60, a, &, c; 61, a, &, c; 62, a, b, c; 63, a, b ; 83, a, b, e. 

 Second, between Gay Head and No Man's Land, and to the westward of 

 the latter island, at localities 82, a, b ; 84, a, b, c, d ; at these localities cod 

 are caught in the spring. Third, on and about the rocky reef extending 

 from Watch Hill, Ehode Island, to Fisher's Island, and forming, in part, 

 the physical boundary of the eastern end of Long Island Sound ; this 

 is also a locality where cod and haddock are caught in spring. The 

 dredgings at this, place were made by Professor D. C. Eaton, Mr. C. A. 

 Burt, and myself, April 13, 1873. Fourth, a locality off Cuttyhunk Island, 

 where dredgings were made, April, 1872, by Mr. T. M. Prudden, Mr. T. 

 H. Eussell, and others. 



The four localities named are characterized by a similar fauna, 

 but each one yielded some species not found in the others, though 

 more numerous dredgings might have revealed them. The reef off 

 Watch Hill is of peculiar interest on account of the singular blending 

 of the northern and southern faunse at that place, as mentioned above. 

 It seems to be nearly at the extreme western range of many northern 

 species, though some of them may occur sparingly in certain favorable 

 localities still farther westward, in Long Island Sound itself. Many 

 northern algae were also collected there by Professor Eaton, in abund- 



