JAPANESE ASTEEOIDEA. 63 



indicate the actual proportions would seem to imply. From the occurrence 

 of both these forms together, as well as the identity of their general struc- 

 iure, it is, perhaps, not improbable that we have here nothing more than a 

 sexual character. 



" Upon the whole, tliis species would seem to be remarkably constant. 

 After a careful study, however, of sx36cimens from Greenland, Novaya Zemlya, 

 and North America, we are inclined to believe that a certain amormt of 

 variation does occui' (probably of locational permanence) in the featm'es of 

 the ventro-lateral plates and of the ambulacral spines, after the manner 

 indicated wliilst treating of the xjhases of growth ; and although this would 

 seem rather like a confusion of the stages characteristic of growth with the 

 features presented by circumstantial variation, the evidence has been such as 

 to lead to the inference that certain characters of early growth-phases are, 

 in some localities, retained luitil a much later period of gi'owth, — perhaps 

 even becoming a permanency through life — a state of things wliich is perfectly 

 esphcable on the not improbable assumption that the exigencies of arctic 

 existence have acted in retarding the progress of growth-characters and in 

 the maintenance of the youthful or more simple form. The spiniilation of 

 the paxillse is similarly subject to variation. 



" Distribution. 



" a. Greenland : Hare Island, Waigat Strait, lat. 70^ 30' N., 175 fms. 

 {'Valorous' Expecl.). 



" b. North of American Continent : Melville Island, about lat. 1^ 47' N., 

 long. 110° 48' W. {Fabry's Exped.) ; Assistance Bay, 7-15 fms. {Penny's 

 Exped.) ; Newfoundland {SABS) ; Bay of Fimdy, 50-60 fms. {StbIPSON) ; 

 Maine. 



'\c. North (f European Continent: Sx^itzbergen (iüTKELV) ; Barents Sea, 

 lat. 76° 58 N., long. 45° 40 E., 110 fms. ( ' Willem Barents ' Exped,), the 

 most noi*thern locaHty on record ; Finmark ; Scandinavian coast." 



According to Ludwig this species is mentioned by Hoffmann ['82]. 

 Vekrill mentions it from the New England coast from depths of 182-310 

 fathoms ['82, p. 218]. 



Danielssen and Koeen mention this species under the name of Cteno- 



