486 
RADIATA. ASTERIAD.®. 
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, LincJc, Stell. 25, t. hi. 20. — Stella marina 
saxis infixa, Borl. Corn. 260, t. xxv. f. 25, 26 — A. gibbosa, Penn, 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, LincTc^ Stell. 27, t. vi. No. 13.— Ast. irreg. Penn. 
Br. Zool. iv. 61, 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, Linclc^ Stell. 21, t. xii. No. 21. ; and p. 22, t. xxxiii. 
No. 53 — A. eq. Sower. Br. Muse. t. Ixiii. 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. 
21. A. aranciaca. — 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 2| 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. Body with five rays, covered with sessile, 
pectinated tubercles, reticularly disposed. 
