486 RADIATA. ASTERIAO.E. Asterias, 



Diameter about 4 inches ; the sides are slightly emarginate, giving the in- 

 dications of the rays. The surface on both sides like shagreen. Dorsally 

 the small tubercles terminate in a brush of short, sharp, nearly equal spines. 

 On the oral disc the spines of the tubercles are unequal, more produced, and 

 pectinated. 



18. A. gibbosa. — Body flat, thick, with very flat, broad, 



short rays, slightly projecting. 



Pentaceros gibbus plicatus, Linck, Stell. 25, t. iii. 20. — Stella marina 

 saxis intixa, Borl. Corn. 2G0, t. xxv. f. 25, 2C — A. gibbosa, Perm. Br. 

 Zool. iv. 62. Turt Brit. Fauna, 149. — English shores. 



Diameter scarcely an inch ; upper surface uniform, without the obsolete 

 ridges of the preceding ; the dorsal tubercles are more crowded, and the 

 spines blunter ; below, the tubercles support fewer, thicker, and longer spines. 



** Body divided into short rays, coriaceous above, with a bor- 

 der of large plates or scales on the margin. 



19. A. irregularis. — The dorsal marginal plates subhastate, 

 the oral ones subrectangular, lengthened, contracted in the 

 middle, each supporting three or four short pectinated spines. 



Astropecten irregularis, Linck, Stell. 27, t. vi. No. 13.— Ast. irreg. Penn. 

 Br. Zool. iv. 01, No. 57. — South of England. 

 The dorsal surface is gibbous, with small plates, reticularly disposed ; oral- 

 ly the plates are long, and arranged in rows parallel with the margin. Ave- 

 nues of pores protected by short thick spines. Diameter about 2 inches. 



20. A. equestris. — Marginal plates oblong, and covered with 



tubercles, having a central eminence surrounded by a moniliform 



ring. 



Pentaceros planus, Linck, Stell. 21, t. xii. No. 21. ; and p. 22, t. xxxiii. 



No. 53 A. eq. Sower. Br. Muse. t. lxiii. Turt. Br. Faun. 140, No. 



129 Shores of Scotland, not common ; Murray Frith, James Bro- 



die, Esq. ; Frith of Forth, Patrick Neill, Esq. 



About 4 inches in diameter, and about an inch thick in the middle ; co- 

 vered on both sides with tubercles similar to those on the marginal plates, 

 some of which, on the dorsal disc, have the central eminence oblong, and di- 

 vided in the middle like the jaws of a vice. 



SI. A. arajiciaca. — Rays depressed, lanceolate, marginal 

 plates transversely oblong, with a rough granulated surface. 



Mull. Zool. Dan. t. Ixxxiii. Linn. Syst. i. 1100 — Leith shore, Dr 

 Coldstream. 

 Diameter (with the rays) about 2A inches ; disc above the body and rays 

 closely covered with short granular tubercles ; the marginal plates are 

 raised, rounded, and rough, each bearing four or five spines on the edge ; the 

 under surface of the plates is covered with short imbricated spines, the cen- 

 tral margin pectinated. 



*** Body deeply divided into rays. 



22. A. rubens. — Body with five rays, covered with sessile, 

 pectinated tubercles, reticularly disposed. 



