118 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [412] 
Polyps. 
Page. | Page. 
Metridium marginatum.... 329 | Astrangia Dane .......... 408 
Sagartia leucolena......... 329 
PROTOZOA. 
Sponges. 
Page. | Page. 
Gramilavciwiata. ..< ss. 2c. 330 | Chalina oculata ....... ->- , 409 
Cliona sulphurea........-- 409 | Chalina, slender species.... 409 
PRADA: -) joc.2 eh ee 409 | Several other sponges... . - 409 
Sponge, red species.-....-- 409 
Foraminifera. 
Numerous, species: s-. ioe tates: See ad oasee cee ee 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 witha considerable proportion of dead and usually broken shells, 
were of frequent occurence in Vineyard Sound, and 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 conteuts 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 
Jornicata, 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 ‘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 
