the Echinodermata of the Arctic Expedition. 453 



characters of sufficient importance to warrant their separation 

 from the drdbachiensis group, although when isolated and 

 extreme examples are compared the differences at first sight 

 appear very marked. 



Similarly wath the specimens collected by the recent expe- 

 dition, separate individuals placed by the side of a single S. 

 drdbachiensis from a more southern habitat present super- 

 ficially a striking divergence. 



Of these arctic forms the test is depressed, the spines of the 

 abactinal surface so small (merely miliaries) and so widely 

 spaced that the echinus has quite a naked appearance. The 

 pores are arranged in arcs of 5-6. The primary tubercles are 

 large, only one to each plate, and form prominent vertical 

 rows. The scrobicular areas are wide and bounded by an 

 irregular circlet of tubercles little larger than miliaries ; and 

 there are but few other tubercles in addition to these on the 

 plates above the ambitus. Extending from the actinostome 

 to the ambitus there is a moderate-sized secondary tubercle on 

 each side of the primary. 



All the specimens present the appearance of stunted growth. 



The colour of the test is a varying shade of purplish brown, 

 and that of the spines greenish grey. 



On some examples the pedicellarife are remarkably nume- 

 rous, especially the large tridactyle form on the abactinal 

 surface. 



Good series of specimens were obtained at several stations, 

 and in general facies present great constancy of character. 



The largest individual (from Cape Xapoleon) measures 43 

 millims. in diameter, 21 millims. in height, and has twenty 

 primary interambulacral tubercles. 



ASTEROIDEA. 



Asteracanthion grbnlandicus, Steenstrup. 



?Ura8ter violaceus, Forbes (pars) (non Miiller), Sutherland'd Journ. 



Append. 

 Asteracanthion 3Iulleri, Sars ?, var., Steenstrup, Vid. Meddel. 1854, 



p. 240. 

 A. Miilleri, Stimpson, Invert. Grand Manan. 

 A. qronlandicus, Steenstrup, Videusk. Meddel. Irf54, p. 240; Liitken, 



Vid. Meddel. 1857, p. 29. 



Coll. Feildcn : Discovery Bay, 25 fms. ; Cape Fraser, 

 80 fms. ; Hayes Point, 25 fms. ; Franklin-Pierce Bay, 

 15 fms. 



Coll. Hart : Franklin-Pierce Bay, 13-15 fms., stony. 



This is a small starfish, with five moderately thick arms. 

 Proportion of disk-radius to arm-radius 1 : 4*5 or 5. Arabu- 



