PENTAGONASTER. 



PENTAGONASTERID.E {see p. 21). 

 PENTAGONASTERDLE (see p. 21). 



Key to the Genera of Pentagonasterinse. 



Body pentagonal 1. Pentagonaster, p. 73. 



Body with elongated arms 2. Nymphaster, p. 75. 



Incertce sedis. 

 Marginals indistinct 3. Hippasterias, p. 76. 



1. PENTAGONASTER. 



Pentagonaster, C. F. Schultze, Betr.verst. Seesteme, (1760) p. 50; Perr. 



Arch. Zool. exp. v. (1876) p. 6 ; Sladen, Chall. Rep. Ast. (1889) p. 264. 

 Goniaster (pars), Ag. Mem. Soc. Neuch. i. (1836) p. 191 ; M. Tr. 



Arch.f. Nat. vi. (1840) p. 322. 

 Astrogonium, M. Tr. (pars) Syst. Ast. (1842), p. 52 ; Sladen, Chall. 



Rep. Ast. (1889) p. 263. 



Body flat, pentagonal, sides nearly straight ; marginals not 

 numerous, usually covered with gramiles ; dorsal intermediate 

 plates hexagonal or irregular in form, covered with flat granules and 

 extending to the ends of the rays ; no valve-like pedicellariae. 



Key to the Species. 



R is less than 2 r 1. P. granulans. 



R is more than 2 r 2. P. greeni. 



1. Pentagonaster granulans. (Plate X. figs. 4, 5, & 6.) 



Asterias granulans, Retzius, Vet.-Akad. Hdlg. iv. ( 1783) p. 238 ; 



Abilg. in Zool. Dan. iii. (1788) p. 19, pi. xcii.; Retz. Diss. Spec. 



Ast. (1805) p. 10. 

 Asterias tessellata, var. A, Lamk. An. s. Vert. ii. (1816J p. 552 ; 



id. op. cit. 2nd ed. (1840) iii. p. 238. 

 Astrogonium granulare, M. Tr. Syst. Ast. (1842) p. 57; Sars, 



Norg. Ech. (1801) p. 46. 

 Astrogonium boreale, Barrett, Ann. § Mug. xx. (1857) p. 47, pi. iv. 



tig. 5. 

 Gouiaster granulans, Lath. Vid. Medd. 1864 (1865), p. 146. 

 Pentagonaster granulans, Kor. §• Dan. Norske Norhavs Ast. (1884) 



p. 58 ; Sladen, Chall. Rep. Ast. (1889) p. 268. 

 Pentagonaster balteatus, Sladen, I'roc. R. Irish Acad. i. (1891) 



p. 688, pi. xxv. 

 Pentagonaster cono-innus, id. t. c. p. 690, pi. xxvi. 



R = l-3rto 1-4 r. 



Small, sides slightly curved. About seven supero- and infero- 

 marginals on either side of each arm with a single terminal plate. 

 Ambulacra very narrow, bordered by two rows of spines, of which 

 there are two or three on each plate ; those of the inner row are 



