CLASSIFICATION. 41 



2. AsTROPECTEN, Linck. — Ambulacral spines simple, linear, without any tesserae between 



the marginal tubercles near the mouth and angles of the arms. A. cornicidaius, 

 Linck., Stel. Mar., t. 27 and 36. 



3. LuiDiA, Porb. — Margin of the flat rays erect; dorsal surface crowded with regular 



paxillse. L. fragillissima, Forbes, Brit. Star-fishes, p. 135. 



4. Petalaster, Gr. — Margin of the rays shelving ; dorsal surface with equal paxilla: 



placed in longitudinal and transverse series. Asiatic, P, Hardwicldi, Gr., Brit. Mus. 



5. SoLASTER, Forb. — Rays many, with two series of broad spines bearing tubercles near 



the ambulacra. 8. papposa, Forb., Brit. Star-fishes, p. 112. 



6. Henricia, Gr. — Rays five , rounded, tapering, with rounded tubercles near the ambu- 



lacra ; the dorsal wart obscure, concealed by spines. //. oculata, Penn. 



Family 3. — Pentacerotid^. 



The body supported by roundish or elongated pieces, covered with a smooth or 

 granular skin, pierced with minute pores between the tubercles. 



1. Culcita, Ag. — Type, Asterias Sclmideliana, Retz., Naturforscher., xvi, t. 1. 



2. Pentaceros, Linck. — Body convex above, margin with two rows of large spine- 



bearing tesserae. P. (/ibbus, Linck., Stel. Mar., t. 23, fig. 36. 



3. Stellaster, Gr. — Body depressed, covered with large, flat, regular six-sided plates ; 



margin with two rows of large tesserae ; the lower rows with a series of compressed 

 mobile spines. S. Childreni, Gr., fig. 10. 



4. CoMPTONiA, Gr. — Body depressed, spinose? dorsal and oral disc covered with very 



small, flat plates ; marginal ossicula large, without any mobile spines. 

 C. elegans, Dixons, Fossils of Sussex, t. 22, fig. 9. 



5. Gymnasteria, Gr. — Type, G. sjnnosa, Gr., Brit. Mus. 



6. Paulia, Gr.— Body five-rayed, formed of flat, granulated, spine-bearing, irregular 



ossicula on the disc and margin, without any two-lipped pores. P. Jiorrida, Gr., 

 Brit. Mus. 



7. Randasia, Gr. — Body pentagonal, with a tubercular skin above, and large granular 



plates beneath and on the margin, without any two-lipped slits, but with one or 



6 



