98 ASTEROIDEA. 



Neuch. i. (1836) p. 191; Forbes, Mem. Wern. Soc. viii. (1839) 

 p. 121. 



Uraster, Forbes, Brit. Star/. (1840) p. 78. 



Asteracanthion, M. Tr. Ber. Ak. Berlin, 1840, p. 101 ; iid. Syst. Ast. 



(1842) p. 14 (pars). 

 Diplasterias, Perrier, Miss. Seient. Cap Horn, vi. (1891) p. k 77. 



Arms five, or, if more, not fused so as to form a large disk ; the 

 abactinal skeleton well developed and bearing spines, but not 

 tubercles. 



I have (P. Z. S. 1881, p. 499) made an artificial scheme for the 

 especial object of determining the numerous species of this large 

 genus, but I cannot follow Prof. Perrier (Miss. Seient. Cap Horn, 

 Echinoderm.es [1891], p. le 77) in his division of the genus into 

 Diplasterias, defined as having " Deux rangees de piquauts adambu- 

 lacraires au moins," and Asterias, defined as having " Une seule 

 rangee de piquants adambulacraires ou les piquants alternativement 

 isole's et groupes par deux sur les plaques adambulacraires." This 

 division is, I think, fully met by my groups of " Monacanthida " 

 and " Diplacanthida." 



Key to the Species. 



Spines on upper surface few and large, or moderate 

 and rather more numerous. 



a. Major pedicel la rise scattered 1. A. ylacialis. 



b. Major pedicellarias confined to neighbourhood of 



ambulacral groove 2. A. muelleri. 



Spines small, numerous, irregular. 



a. Arms rounded 3. A. rubens. 



b. Arms flattened 4. A. murrayi. 



c. Arms short and squat 5. A. hispida. 



1. Asterias glacialis. 



Asterias glacialis, Linn. Syst. Nat. x. (1758) p. 661 ; id. op. cit. xii. 



p. 1099; id. ed. Gmel. (1789) p. 3102; O. F. Mull. Zool. Ban. 



( 1 776) p. 234 ; Lamk. An. s. Vert. ii. (1816) p. 561 ; Gray, Ann. § 



May. vi. (1840) p. 179; id. Brit. Bad. (1848) p. 17; Jarzynsky, 



Trans. Petersb. Soc. Nat. i. (1870) p. 318 ; Ludwig, Mitth. zool. 



Stat. Neap. i. (1879) p. 537 ; Greef, Zool. Anz. v. (1882) p. 117; 



Bell, op. cit. p. 282 ; Perrier, Ann. Sci. Nat. xix. (1885) no. 8, 



p. 15 ; Ban-ois, Rev. Biol. i. (1888) p. 69. 

 Asteracanthion glacialis, M. Tr. Syst. Ast. (1842) pp. 14 & 126 ; 



Bub. $ For. Vet.-Akad. Hdhj. 1844 (1846), p. 240; Sars, Nyt 



May. x. (1859) p. 51; id. Nory. Ech. (1861) p. 87; Lorenz, SB. 



Ak. Wien, xxxix. (1860) p. 677; Big. § Hup. Ech. (1862) p. 330; 



Fischer, Actes Soc. Linn. Bordeaux, xxvii. (18G9) p. 364; Moeb. 



4- Butschli, JB. Comm. Kiel, ii. ■& iii. (1875) p. 147. 

 Uraster glacialis, Forbes, Brit. Starf. (1810) p. 78; id. Rep. Brit. 



Assoc. 1843 (1814), p. 149 ; Thompson, Nat. Hist. Irel. iv. (1856) 



p. 438. 

 Asterias spiuosa, Penn. Brit. Zool. iv. (1777) p. 53. 

 Asterias angulosa, O. F. Mull. Zool. Dan. (1788) ii. p. 1, pi. xli. 

 Asterias echinophora, Belle Chiaje, Mem. An. Nap. ii. (1825) p. 356, 



pi. xviii. tig. t>. 

 Sfelloaia angulosa, Ay. Mem. Soc. Neuch. i. (1836) p. 192. 



