ASTEROIDEA. 23 
Family 3. CORETHRASTERIDA*, 
Korethrasteride, Dan. § Kor. Norsk. Nordh. Exp., Aster. (1884) 
p. 99. 
Allied to the Asterinids, but distinguished by the complete 
absence of interbrachial spaces, and by the possession of a con- 
tinuous calcareous plating, and the formation of the paxille. 
One genus: Corethraster. 
Family 4. PTERASTERIDA. 
Pterasteridee, Perrier, Arch. Zool. iv. (1875) p. 302; Viguier, op. cit. 
vii. (1878) p. 224; Perrier, Nouv. Arch. Mus. vi. (1884) p. 216; 
Sladen, Chall. Rep. Ast, (1889) p. xxxvii. 
Velate, Perrier, Miss. Cap Horn, vi. (1891) p. k 72. 
Cryptozonate Asteroidea in which the dorsal ossicles carry a spine 
crowned by long diverging spines which support a more or less well- 
developed membrane ; this forms a marsupial recess for the young. 
No actinal intermediate plates, interbrachial septa, or pedicellarie. 
Two genera: Pteraster and Hymenaster. 
Family 5. ECHINASTERID A. 
Echinasteridxe, Verrill (no diagnosis), Trans. Conn. Acad. i. (1867[71}) 
p. 343; Perrier, Arch. Zool. iv. (1875) p. 299; Viguier, op. cit. vil. 
(1878) p. 121; Perrier, Nouv. Arch. Mus. vi. (1884) p. 206; Sladen, 
Chall. Rep. Ast. (1889) pp. xxxviii & 535. 
One subfamily. 
Subfamily ECHINASTERIN #. 
Echinasterine, Viguier, Arch. Zool. expér. vii. (1878) p. 123; Sladen, 
Chall. Rep. Ast. (1889) p. xxxviii. 
Kchinasteride with rather small disk and five or six rays ; spines 
small, simple, solitary or grouped. No pedicellariz. 
One genus: Henricia. 
Family 6. ASTERIID. 
Asteriadee, Gray, Ann. § Mag. vi. (1840) p. 178; Norman, Ann. 
§ Mag. xv. (1865) p. 125; Perrier, Arch. Zool. iv. (1875) p. 299; 
Viguier (s. em.), op. ett. vii. (1878) p. 93; Perrier, Nouv. Arch. 
Mus. vi. (1884) p. 199. 
Urasterie, Forbes, Brit. Starf. (1840) p. 77. 
Erste Familie, M. Tr. Syst. Ast. (1842) p. 11. 
* The only specimen available to me is the type of Wyville Thomson, which 
has been investigated by Mr. Sladen. 
