170 PROCEEDINGS OF THE ACADEMY OF [Feb., 



Florida reefs, 24° N. L. on the west, and Plymouth, England, 



50° X. L. on the east of the Atlantic, to Spitzbergeu, 80° N. L. 



Its vertical distribution ranges from to 220 fathoms on the 



west coast of Iceland. The usual depth is from 3 to 30 fathoms. 



2. Myriotrochus rinkii Steeiistmp. 



3IyriotrochiLS rinkii Steeustrup, Videnskabelige Meddelelser Xaturhist. 

 Forening i Kjobenbavn, pp. 55-60, PI. Ill, figs. 7-10, 1851 ; Theel, 

 Challenger Reports, Zoology, Vol. XIV, Holothuria, p. 37, 1886. 



Station 9 Saunders Island, 5-10 fathoms. 1 specimen. 



Station 45. Barden Bay, 10-45 fathoms. 32 specimens. 



Distribution. — West coast of Greenland to Discovery Bay 

 (Nares Ex.), Assistance Bay (Penny's voyage); east coast of 

 Greenland, Spitzbergen, Barents Sea, Nova Zembla, Kara Sea, 

 Bering Sea, Point Barrow. 



As Cucumaria frondosa, this also is a two-thirds circum[)olar 

 form, being absent in the north Asian region, 71° E. L. to 170° 

 W. L., and in the North American, 156° W. L. to 95° W. L. 



It is a strictly Arctic form, its extreme points of distribution 

 north and south being 81° 41' N. (Discovery Bay) to 57° N. 

 (Skager Rak). 



It belongs principally to the littoral region, but has been dredged 

 at a dej)th of 360 fathoms, 



ECHINOIDEA. 



3. Strongylocentrotus drbbacliiensis (O. F. Miiller). 



Echinus drobacMensis O. F. IMiiller, Zool. Dan. Prodr., p. 235, 1776. 

 Stronfjylocentrotus drbhacMensis A. Agassiz, Revision of the Echini, 

 111. Cat. Mus. Comp. Zool. Cambridge, pp. 162-267, 1872. 



Station 17. Payer Harbor, Cape Sabine, 16 fathoms, 2 

 specimens. 



Station 26. South of Cape Alexander, 27 fathoms. 2 speci- 

 mens. 



Station 29. Olriks Bay, lower narrows, 7-25 fathoms. 7 speci- 

 mens. 



Station 34. Cape York, 10 fathoms. 3 specimens. 



Station 39. Granville Bay, 30-40 fathoms. 8 specimens. 



Station 49. Olriks Bay, upper narrows, 15-20 fathoms. 1 spec- 

 imen. 



Station 50. Karnah, 30-40 fathoms. 11 specimens. 



Station 51. Robertson Bay, 35-40 fathoms. 30 specimens. 



