KEPOKT ON THE ASTEKOIDEA. 189 



2. Leptoptychaster arcticus, Sars, sp. 



Aslropectcn arcticus, Sars, 1851, Roise i Lofoten og Finmarken, Nyt Mag. f. Naturvidensk., Bd. vi. 



p. 161 ; Fauna Litt. Norvegiae, 1856, Heft 2, p. 61, pL ix. figs. 16-18 ; Oversigt af Norges Eehino- 



dermer, 1861, p. 32. 

 Astropecten Liitkeni, Barrett, 1857, Ann. and Mag. Nat. Hist., ser. 2, vol. xx. p. 46, pi. iv. fig. 3, a, b, c. 

 Archaster arcticus, Perrier, 1878, Nouv. Archives Mus. Hist. Nat., 2e Ser., t. i. pp. 32, 88. (Also 



Verrill, and Storm). 



Localities. — " Porcupine " Expedition : 



Station 65 (1869). Between the Shetland and the Faeroe Islands. Lat. 61° 10' N., 

 long. 2° 21' W. Depth 345 fathoms. Bottom temperature — 1°-1 C. ; surface tempera- 

 ture, 11°-1 C. 



Station 82 (1869). In the Faeroe Channel. Lat. 60° 0' N., long. 5° 13' W. Depth 

 312 fathoms. Bottom temperature 5°"2 C. ; surface temperature 11°*2 C. 



Station 3 (1870). 1 West of Ushant. Lat. 48° 31' N, long. 10° 3' W. Depth 690 

 fathoms. 



Remarks. — This form was originally described as an Astropecten. Some subsequent 

 writers have retained it in that genus, whilst others have regarded it as an Archaster. 1 

 am uuable to agree with either of these determinations. After careful study I consider that 

 its structure accords in all points of generic import with the genus Leptoptychaster estab- 

 lished by Mr Smith for the foregoing form from the Southern Ocean, and I have therefore 

 referred the species under notice to that genus. It is readily characterised by the aborted 

 supero-marginal plates, the short but broad infero-marginals (both alike unarmed), the 

 well-developed actinal interradial areas, the character of the paxdlae, and likewise that 

 of the armature of the adambulacral plates. Finally, the species has more or less well- 

 developed superambulacral plates ; the whole forming a combination of characters which 

 accords neither with Archaster nor Astropecten. 



2a. Leptoptychaster arcticus, var. elongata, nov. 



The American examples of this species, of which a large series was taken at Station 49, 

 are all distinctly longer in the ray, and have the paxillse of the abactinal area some- 

 what more delicate and less compact in character than in the European forms, although 

 even in these some variation occurs. It would, however, be an easy matter to say which 

 were the American examples out of a large number of mixed specimens, and on these 

 grounds I consider that we are dealing with a well-marked variety. 



Localities. — Station 46. Off the coast of North America, east of New Jersey and 

 Long Island. May 6, 1873. Lat. 40° 17' 0" N, long. 66° 48' 0" W. Depth 1350 

 fathoms. Blue mud. Bottom temperature 37°-2 Fahr. ; surface temperature 40°-0 Fahr. 



1 Recorded by Sir Wyville Thomson in The Depths of the Sea ; but I have not seen a specimen from this 

 locality. 



