118 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [412] 



Polyps. 



Page. 



Metridium marginatum 329 



Page. 



Astrangia Dana', 408 



Sagartia leucolena 329 



PROTOZOA. 



Sponges. 



Page. 



Grantia ciliata 330 



Cliona sulphurea 409 



Tedania . 409 



Page. 



Chaliua oculata 409 



Chalina, slender species 409 



Several other sponges. . 409 



Sponge, red species 409 



Foraminifera. 



Page. 

 Numerous species 421 



6. FAUNA OF THE GRAVELLY AND SHELLY BOTTOMS OF THE BAYS 



AND SOUNDS. 



Bottoms composed of gravel or pebbles, often with small stones, and 



generally with a considerable proportion of dead and usually broken shells, 



were of frequent occurence in Vineyard Sound, arid a few such localities 



were found in Buzzard's Bay. Similar bottoms of small extent have 



also been examined in Long Island Sound, near New Haven. These 



bottoms are generally the most productive and agreeable for the 



dredger, for they are the favorite abodes of large numbers of animals 



of all classes, and the contents of the dredge are often so clean that 



they require little if any washing in the sieves. They vary much, 



however, in character, some of them consisting mostly of gravel, with 



pebbles and perhaps small scattered boulders ; others consist largely 



of broken shells, especially those of Mactra solidissima and Crepidula 



fornicata, mixed with more or less gravel, sand, and mud. Others 



are so completely overgrown with the various large compound asci- 



dians described above, that they might well be called u ascidian 



bottoms." In many places, however, there are patches of mud or sand, 



scattered here and there over a bottom which is mostly of gravel and 



shells, so that the dredge will often bring up more or less mud or sand, 



with some of the animals peculiar to such patches, mixed with those 



peculiar to the gravelly bottoms, thus augmenting the number and 



variety of animals. In other cases more or less mud and sand may be 



mixed with the gravel throughout, or the bottom may be in process of 



changing from mud or sand to gravel, or the contrary, owing to frequent 



changes in the directions of the currents, produced chiefly by the action 



of storms upon the shoals and bars of sand. Hence it is often difficult to 



