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 Christi, Diiben and Koren, 1844, Ofvers. k. Svensk. Vet.-Akad. Férhandl., p. 113. 
Archaster Andromeda, Mobius and Biitschli, 1875, Jahresb. d. Comm. z. wiss. Untersuch. d, deutsch. 
Archaster Christi, Perrier, 1876, Révis. Stell. Mus., p. 347 (Archives de Zool. expér., 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. 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? 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,’ and Danielssen 
and Koren,! and also the description given by Diiben and Koren.’ 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 “gelatinést éfverdrag ;”* 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. 
5 K. Svensk. Vetensk.-Akad. Handl. Ar 1844 (1846), p. 250. 
6 Loc. cit., p. 251. 
