506 EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



RADIATA. 



Eclilnoderms. 



Page. 



tStereoderma uiiisemita 503 



t*EcliiDaraclinms par ma. . . . 503 

 Strongyloceutrotus Drobach- 

 iensis 406 



Page. 



Asterias vulgaris 496 



*Oribrella sanguiuolenta. . . 407 

 Ophiopholis aciileata 496 



Aealephs. 



Page. 



*Platypyxis c^iiodrica 408 



*01y tia JohDstoni 408 



Eudendrium ramosum 408 



Page. 

 *Pliimulariaj sp 407 



Hydractinia polyclina. .... 328 



Folyps. 



Page. 



Edwardsia lineata 497 



Page. 

 Alcyoiiium caraeiim 497 



PROTOZOA. 



Sponges. 



Page. 



Ghalina oculata 497 



Polymastia (?) 497 



Page. 



fMassive siliceous sponge . . 503 



IV. 5. — Fauna of the muddy bottoms off the open coast. 



Within the depths to which our dredgiugs extended, very few true 

 muddy bottoms occur. The deposits of mud on the open coast usually 

 begin to occur only at the depths of twenty five to thirty fathoms, and 

 even at these depths there is a considerable admixture with fine siliceous 

 sand. The central and deeper portion of the depression in line with the 

 axis of Vineyard Sound is, however, occupied off to the west of Gay 

 Head and No Man's Land by a deposit of fine, soft, sticky mud, filled 

 with the tubes of Annelids and Amphipods, {Ampelisca, &c.) Dredgings 

 were made on this bottom at localities 85, c, in 18 fathoms j d, 19 fathoms; 

 e, 11 fathoms. On September 9, the temperature at 85, c, was 58^ Fah- 

 renheit at the bottom, and 62^ at the surface; at d, it was 57° at the 

 bottom and 62° at the surface ; at e, it was 59° at the bottom and 63^ at 

 the surface. This muddy bottom abounded in Annelids, small Crustacea, 

 and bivalve shells. 



In several other localities, where the bottom was a mixture of mud 

 and fine sand, the mud seemed to predominate and to determine the 

 character of the life, so that such localities have been classed with the 

 muddy bottomvS, though the fauna differed considerably from that of the 

 soft muddy bottoms referred to above. In the following list, however, I 

 have specially designated the sj>ocii\s found in the typical localities of 

 each kind. 



