420 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



which forms branching, coral-like masses on the slender red algse ; a 

 species of LepraUa, found with the last, and also on.shells, which is allied 

 to L. Pallasiana of Europe; Mollia hyctlina, which forms circular disks, 

 with irregular, more or less oblique cells; and Membranipora tenuis, 

 which is common on the pebbles, often covering their whole surface with 

 a delicate lace-like incrustation, made up of very small, crowded, oval 

 or oblong cells, which have the inner part of the front partly closed over, 

 but with an irregular, mostly three-lobed aperture toward the outer end, 

 which is bordered by small, irregular spinules. 



The Vesicularia fusca was also found in a few instances, in deep water. 

 It had not been previously known on the Amefican coast. Good speci- 

 mens of the Caberea Elllsii were also dredged in the deeper parts of Vine- 

 yard Sound, attached to ascidians. 



Of Echinoclerms the number of species is not large. The common 

 green star-iisk, Asterias arenicola (Plate XXXV, fig. 269) is very com- 

 mon; the Cribrella sanguinolenta, (p. 407,) is comparatively rare ; and 

 the green sea-urchin, S. Drobachiensis, (p. 406,) is quite infrequent. 

 The purple sea-urchin, Arbacia punctulata, (p. 326,) is, however, quite 

 common in many localities. The largest and finest specimens were 

 taken off Holmes' Hole, but it was quite abundant, though of moder- 

 ate size, in Great Harbor and Wood's Hole passage. The Thyone Bria- 

 reus (p. 362) is not uncommon in shallow water, especially among weeds; 

 it has already been mentioned, (p. 418,) as carrying Eulima oleacea 

 attached to its skin. 



Another Holothurian, the Pentamera pulchella, seems to be quite com- 

 mon, judging by the numerous specimens thrown on Kobska beach by 

 the storms, and preserved for us by Mr. Vinal N. Edwards, during the 

 past winter, but it was dredged only in one locality, off Holmes' Hole, 

 by Messrs. T. M. Prudden and T. H. Eussell. It is a southern species, 

 not previously known north of the Carolina coasts. It is easily distin- 

 guished from the preceding species by its light color, and by having 

 the locomotive-suckers arranged in five broad and very distinct longi- 

 tudinal bands, with naked spaces between them. 



A very delicate little Ophiurian, the Ampliipliolis elegans, was occa- 

 sionally met with on the shelly bottoms. This is a northern species, 

 much more common in the Bay of Fundy, where it is found from low- 

 water mark to 80 fathoms, and it is found also on the northern coasts 

 of Europe. It has a nearly circular disk, covered with smooth scales, 

 regularly arranged, and each of the scales, on the sides of the slender 

 rays, bears three short, blunt spines. Its color is usually light gray or 

 whitish, frequently more or less marked with dark gray or brown. 



The Hydroids are numerous on these bottoms, and mostly of the same 

 species that have been mentioned as occuring on rocky bottoms. 



The Polyps are few and essentially the same as those on the rocky 

 bottoms. The only additional species was a small, slender, undescribed 



