70 ASTEEOIDEA. 



peculiarly modified spines ; interbraehial spaces closely beset with 

 pedicella'ria-like scales. Marginals confined to the sides of the 

 arms ; the dorsal paxillar area free of pores on the disk and along 

 the middle of the arms. Anus present or absent. The adambu- 

 lacrals form a series of angles which project into the ambulacral 

 groove, and bear spines on either side. No epiproctal cone. 



1. Bathybiaster vexillifer. 



Archaster vexillifer, Wyv. Thorns. Depths of the Sea, (1873) p. 150, 



fig. 25. 

 Astropecten vexillifer, Viguier, Arch. Zool. exper. vii. (1878) p. 240. 

 Bathybiaster vexillifer, Sladen, Chall. Rep. Ast. (1889) p. 243 



Bell, P. Z. S. 1891, p. 228, pis. xxiii. & xxiv. 



R = 5 r. 



Arms and disk flat ; the former with deep vertical sides formed 

 by the marginals, of which there are about 70 in each row : those 

 of the superomarginal series have each a single short spine near the 

 upper edge, and the inferomargiual similar and subequal spines near 

 the upper and lower edges. The adambulacral spines are arranged 

 by fours on two sides of a triangular plate, the apex of which bears 

 a spine. Connected with this spine is a grooved spiniform body or 

 " vexillum," the edges of which are finely denticulated. A small 

 anal orifice. Madreporite small, near margin of disk. 



a. Faeroe Channel, 344 fms. ' Porcupine ' Exp. (St. 76). 



Unique specimen. 



LUIDIIN^E (see p. 21). 



LUIDIA. 



Luidia, Forbes, Mem. Wern. Soc. viii. (1839) p. 123 : M. Tr. Syst. 



Ast. (1842) p. 77; Norm. Ann. # Mag. xv. (1865) p. 117; A. Ag. 



Mem. Mus. C. Z. v. (1877) p. 117 ; Vig. Arch. Zool. exper. vii. (1878) 



p. 228 ; Sladen, Cliall, Rep. Ast. (1889) p. 244. 

 Hemicnemis, M. Tr. Ber. Ah. Bed. 1840, p. 104. 

 Petalaster, Gray, Ann. # Mag. vi. (1840) p. 183. 



A Luidiine with elongated, flattened rays, frequently more than 

 five in number, and exhibiting a marked tendency to break off with 

 great power of repair. 



Key to the Species. 



Seven or eight rays 1 . L. ciliaris. 



Five rays 2. L. sarsi. 



1. Luidia ciliaris. 



Asterias rubens, Johnston (noft Linn.), Loudon's Mag. Nat. Hist. vs. 



(1836) p. 144, fig. 20. 

 Asterias ciliaris, Philippi, Arch. f. Nat. iii. (1837) p. 194. 



