16 MARINE INVERTEBRATA OF GRAND MAN AN. 



which it resembles. There are also sometimes found specimens of a bright reddish 

 or purplish coloi', depressed, and about two inches in diameter ; these resemble E. 

 neglectus, Forbes, D. et K. 



EcHiNARACHNius Atlanticus, Gray. Very common on sandy shores at low water. 



HOLOTHURIADiE. 



CuviERiA Fabrich, Dub. et Kor. Eolothuria squamata, Gould, Inv. Mass. Small 

 specimens were dredged abundantly among nullipores in five fathoms, and a number 

 of very large ones were found attached to the under surface of large shelving rocks 

 in the fourth subregion of the littoral zone. The largest was four inches in length, 

 while its tentacles had a spread of nearly five inches, and presented a beautiful 

 area of bright red waving plumes. 



PsoLUS PHANTAPUS, JoBger. P. IcBvigatus, Ayres, Bost. Proc, iv. 25. Common in 

 forty fathoms, attached to small stones; and occasionally found at low-water mark. 

 These were all small specimens. The large ones seem to live buried among 

 pebbles ; thus, at Eastport, one was dug from a depth of six inches in gravel. This 

 measured three inches in length. 



OcNUS Atkesii, St., n. s. Completely encased in calcareous matter in the form of 

 polygonal plates somewhat variable in size, but usually equalling in area one-half 

 that of the disk of the sucker. These plates have regular and equal perforations 

 in quincunx, smaller in width than their interspaces. The suckers are stout, and 

 are distributed distantly in five rows, in the three ventral of which they are much 

 larger than in the two dorsal. There are about seven suckers in each row, which 

 are encased in the calcareous plates on their sides. The tentacula are short, and 

 have few blunt branches. The color is white, or pale fawn. Length usually two- 

 tenths of an inch; breadth 0.15 inch. Dredged on shelly bottoms in twenty-five 

 fathoms. 



Duben and Koren include the genus Ocnus of Forbes in Cucumaria (Pentacta), 

 and seem to consider the small number of feet or suckers as resulting from the 

 immaturity of the specimens yet examined. But having seen a large number of 

 specimens of the species now proposed as new, none of which exceeded three-tenths 

 of an inch in length, I am led to consider the fewness and large comparative size 

 of the feet as constant ; adding to it a character not in Forbes's diagnosis ; — the 

 crowded perforated plates, which will always serve to distinguish the species of 

 this genus from young Pentactce, and by which it forms a connecting link between 

 this latter genus and Psolus. 



Pentacta frondosa, Jteger. Cucumaria frondosa, Forbes, Dub. et Kor. Botryo- 

 dacUjla grandis, Ayres, Bost. Proc, iv. 52. B. ajfinis, Ayres, id. 145. Nothing 

 can exceed the profusion in which this species exists in some parts of the islands. 

 It is found just below the ordinary low-water mark on rocky shores, and is, there- 

 fore, exposed at spring tides. I have seen areas of several square rods entirely 

 occupied by them. The largest observed was nine inches in length and three wide. 

 They, are usually black or dark purple above, and pale brown or yellowish below. 

 Some specimens are of a uniform bright yellow. They always adhere by one side — 



