A MEMOIR 



ON THE 



ECHINODERMATA OF THE ARCTIC SEA 



TO TIIE 



WEST OF GREENLAND, 



HOLOTHTTROIDEA. 



JUDGING from the results of such dredging as has hitherto been conducted in high 

 latitudes, the Holothuroidea as a group do not appear to extend in the North-Atlantic 

 area to a very great distance within the Arctic Circle. Exception must be made, 

 however, in the case of Myriotrochus Rinkii, Stp., which was obtained by the Polar 

 Expedition of 1875-76 in Discovery Bay, lat. 81 41' N., the most northern locality at 

 which any Holothuroid has yet been found. The other members of the order have not 

 been recorded in this area beyond the 70th parallel ; but as they occur in higher lati- 

 tudes elsewhere, it has been deemed expedient to include those which extend beyond 

 the Arctic Circle (66 30' N.) in the present description. 



The following is a list of the Holothuroids in question : 



1. Cucumaria frondosa (Gunner), Forbes. 



2. Cucumaria calcigera (Stimp.), Selenka. 



3. Orcula Barthii, Troschel. 



4. Psolus phantapus (Strussenf.), Jager. 



5. Psolus Fabridi (D. & K.), Liitken. 

 C. Chirodota Icevis (Fabr.), Grube. 



7. Myriotrochus Rinkii, Steenstrup. 



B 



