CHETLASTER. — LASIASTER. 81 



3. CHEILASTER. 



Marginaster (vox hybr.), Perrier, Bull. Mus. Comp. Zool. ix. (1881) 

 p. 16 (n. n.); id. Nouv. Arch, du Mus. iv. (1884) p. 229; Sladen, 

 Chall. Rep. Ast. (1889) p. 364. 



No more than Mr. Sladen, who temporarily accepts the genus, 

 can I, who have only seen one specimen, and that one of 12 millim. 

 in diameter, add anything to Prof. Perrier's diagnosis, which does 

 not err on the side of length. It runs thus : — 



" Petites asteries pentagonales ou a bras peu marques ; ossicules 

 recouverts par un tegument mince ; ossicules eux-memes dulicats ; 

 d'ordinaire legerement epineux. — Corps borde par une double rangee 

 de plaques marginales bien distinctes." 



1. Cheilaster fimbriatus. 



Marginaster fimbriatus, Sladen, Chall. Rep. Ast. (1889) p. 365, 

 pi. lviii. tigs. 4-6. 



R = 6 ; r = 5 mm. 



Mr. Sladen distinguishes this species as having groups of granules 

 on the abactinal plates, but no comb of spinelets on the supero- 

 marginal plates ; it has a row of spinelets on the actinal interradial 

 areas set parallel to the margin. 



a. 56° 15' N., 11° 25' W., 1360 fms. * Porcupine ' Exp. (Type.) 



4. LASIASTER. 



Lasiaster, Sladen, Chall. Rep. Ast. (1889) p. 371. 



In cataloguing this genus I must repeat the word of warning I 

 gave under Rhegaster, and I must disclaim any share of respon- 

 sibility for the introduction of another genus based on two small 

 specimens, which are recognized as being immature. It differs 

 from She g aster in having well-developed superomarginal plates, and 

 there is consequently a thick wall-like side to the body. All the 

 intermediate plates bear isolated groups of spinelets. 



1. Lasiaster villosus. 



Lasiaster villosus, Sladen, CJiall. Rep. Ast. (1889) p. 372, pi. lviii. 

 figs. 7-10. 



I am unable to deduce from Mr. Sladen's description the specific 

 diagnosis of this form, and as the only two specimens I have seen 

 are immature I cannot draw up one myself. The figures will show 

 the student all he can be told. 



a, b. 59° 34' N., 7° 18' W., 542 fms. ' Porcupine ' Exp. (Types.) 



