224 THE VOYAGE OF H.M.S. CHALLENGER. 



1. Psilaster andromeda, Miiller and Troschel, sp. 



Asterias aranciata (varietas), Parelius, 1768, K. Norske Vidensk. Selskabs Skrifter, vol. iv. p. 426, 



tab. xiv. figs. 5, 6. 

 Astropecten Andromeda, Miiller and Troschel, 1842, System der Asteriden, p. 129. 

 Astropecten Cliristi, Diiben and Koren, 1844, Ofvers. k. Svensk. Vet.-Akad. Forhandl., p. 113. 

 Archasier Andromeda, Mdbius and Biitschli, 1875, Jahresb. d. Comm. z. wiss. Untersuch. d. deutsch. 



Meere in Kiel, f. d. Jahre 1872-73 ; ii. iii. Jahresb., iv. Echin., p. 148. 

 Archaster Ckristi, Perrier, 1S76, Revis. Stell. Mus., p. 347 (Archives de Zool. exper., t. v. p. 267). 

 Goniopecten chisti, Perrier, 1885, Ann. Sci. Nat. Zool., t. xix., Art. No. 8, p. 71 (err. typ.). 



Localities. — " Porcupine" Expedition : 



Station 76, 1869. 1 West of the Shetland Islands. Lat. 60° 36' N., long. 3° 58' W. 

 Depth 344 fathoms. Bottom temperature — 1°-1 C. ; surface temperature 10° # 1 C. 



Station 3, 1870. 1 West of Ushant, south-west of the Scilly Islands. Lat. 48° 31' N., 

 long. 10° 3' W. Depth 690 fathoms. 



" Knight Errant " Expedition : 



Station 7. August 12, 1880. Lat. 59° 37' N., long. 7° 19' W. Depth 530 fathoms. 



" Triton " Expedition : 



Station 10. August 24, 1882. Lat. 59° 40' N., long. 7° 21' W. Depth 516 fathoms. 

 Bottom temperature 46° Fahr. 



Station 11. August 28, 1882. Lat. 59° 29' N., long. 7° 13' W. Depth 555 fathoms. 

 Bottom temperature 45°'5 Fahr. 



Remarks. — The structure of this form, as indicated in the foregoing generic diagnosis, 

 fully warrants in my opinion its separation from Astropecten; and I have already drawn 

 attention in the remarks following the generic diagnosis, to the prominent characters 

 wherein this species differs from any true member of the genus Astropecten. 



Miiller and Troschel 2 described this species as sometimes furnished with small spinelets 

 on the supero-marginal plates, but I have not noticed their presence in any specimens 

 I have examined. In this respect I can confirm the observations of Sars, 3 and Danielssen 

 and Koren, 4 and also the description given by Diiben and Koren. 5 In the "Knight 

 Errant" specimen all the spinulous or papilliform appendages of the actinal surface 

 are invested with a thick membranous tissue which is often more or less united at 

 their bases, and in some parts coalescent even at their extremities, which are joined 

 by web-like and fibrillar extensions. The appearance thus produced is accurately 

 enough expressed by Diiben and Koren's "gelatinost ofverdrag ;" 6 and I have no doubt 

 whatever as to the correctness of their description in this respect, although the 



1 These occurrences are recorded in Sir "Wyville Thomson's Depths of the Sea, but I have not seen any 

 specimens. 2 System der Asteriden, p. 129. 



3 Oversigt af Norges Echinodermer, p. 30. 



4 Nyt Mag.f. Naturvidensk., 1877, Bd. xxiii. 3, p. 66. 



6 A'. Svensk. Vetensk.-Akad. Handl. Ar 1844 (1846), p. 250. 

 o Loc. cit., p. 251. 



