BATHYBIASTER. 69 



superomarginals have no ridge and are not channelled ; the spines 

 are not enclosed in sheaths, and those on the sides of the ambulacral 

 groove are subequal, numerous, and in a straight row. 



1. Psilaster andromeda. 



Astropecten andromeda, M. Tr. Syst. Ast. (1842) p. 129 ; Dilb. 8f 



Kor. Vet.-Akad. Hdlg. 1844 (1846), p. 250, pi. vii. figs. 18 & 19 ; 



Sars, Norg. Ech. (1861) p. 30: Duj. $ Hup. Echin. (1862) p. 420 ; 



Mob. $ Biitschli, JB. Comm. Kiel, ii. & iii. (1875) p. 148; Kor. 



<§■ Dan. Nyt Mag. xxiii. (1877) p. 65; iid. Norske Nordhavs 



Asteroidea, (1884) p. 81, pi. xiv. fig. 16. 

 Astropecten christii, Diib. 4* Kor. (Efv. Vet.-Akad. Forh. 1844 



(1845), p. 113. 

 Psilaster andromeda, Sladen, Chall. Rep. Ast. (1889) p. 224. 



R = 3-2 r to 4-2 r. 



Arms well marked off from disk, with rather deep sides, tapering 

 regularly but not rapidly to a somewhat sharp point. Ambulacra 

 wide, bordered by a single row of rather delicate spines, of which 

 there are about eight on each plate ; beyond these are three rows of 

 shorter and finer spines, two or three in each row. The infero- 

 marginals are large, much wider than long, bear a few spines and 

 a number of scale-like tubercles, in some cases covered by membrane. 

 The superomarginals, of which there are 30 to 40 on the side of 

 every arm, correspond in number to the inferomarginals ; they are 

 characterized by the presence on them of rather large scales, but on 

 them, as on the lower plates, the central part is, in dry specimens, 

 bare. The plates of the dorsal surface are small, with delicate 

 paxillar spines; the madreporite, which is not conspicuous, is rather 

 nearer the margin than the centre of the disk. 



Distribution. European coast, from Bay of Biscay to Kola Penin- 

 sula. 40-690 fms. 



a. 59° 37' N., 7° 19' W., 530 fms. Vov. ' Knight Errant ' (St. 7). 



b. 59° 40' N., 7° 21' W., 516 fms. Vov. < Knight Errant ' (St. 10). 

 c, d. 59° 29' N., 7° 13' W., 555 fms. VoV. ' Knisrht Errant ' (St. 11). 



e. 50° 29' 26" N., 11° 4' W., 400 fms. G. C. Bourne, Esq. 



4. BATHYBIASTER. 



Bathybiaster, Dan. § Kor. Nyt Mar/, xxvii. (1883) p. 285 ; iid. Norske 

 Nordhavs Aster. (1884) p. 94; Slad. Chall. Ast. (1889) p. 175; 

 Bell, P. Z. S. 1891, p. 230. 



Astropecten (pars), Dan. Sf Kor. Nyt Mag. xxiii. 3. (1877) p. 62. 



Flattened, with very wide ambulacra, at the sides of which lie 



