REPORT ON THE ASTEROIDEA. 175 
Synopsis of the Genera included in the Family Asrropectinpm. 
A. Adambulacral plates touching the infero-marginal plates along the ray. 
Marginal and adambulacral plates not correspondent in length and 
number. Supero-marginal plates more or less well developed. No 
forficiform pedicellaria . c : ° « ASTROPECTININA. 
a. With a webbed marginal fringe a the eal nlates ind to the 
actinal intermediate plates . ; : : . ; - Craspidaster. 
b. With no webbed fringe to the marginal plates or ine actinal inter- 
mediate plates. 
a. Supero-marginal plates with a prominent ridge and specially 
developed fasciolar channels, 
#, Actinal interradial areas small, usually with few inter- 
mediate plates, Paxillee with radiating crowns, 
i. Marginal plates very short and bandlike. Supero- 
marginal plates much smaller than the infero- 
marginal plates, : 5 4 . Leptoptychaster. 
. Marginal plates long and more or nee eer 
Superior and inferior series subequal. : . . Astropecten, 
@. Actinal interradial areas large, with numerous inter- 
mediate plates which imbricate and form trans- 
verse columns. Paxille small, with compact 
erect crowns and long pedicles . 5 A a . Motraster. 
b, Supero-marginal plates plane, with no ridge and no specially 
developed fasciolar channels. 
a, Spinulation simple, not sacculate. Adambulacral arma- 
ture forming a straight series on the furrow mar- 
gin, spinelets numerous and uniform . 5 3 6 . Pesilaster. 
8. Spinulation sacculate. Ambulacral armature forming 
an angulated series on the furrow margin, the 
spinelets few in number, and the median one of 
a different shape from the rest, 
i. Well-developed epiproctal cone. No pedicellarie . 5 » Phoxaster. 
ii. No epiproctal cone. Sacculated spinelets of the 
actinal area forming modified pedicellaria , 0 . Bathybiaster. 
B. Infero-marginal plates separated from the adambulacral plates by a small 
intermediate plate throughout the ray. Marginal and adambulacral 
plates correspondent in length and number. . 5 » Lorpi2. 
a. Supero-marginal plates aborted. Adambulacral plates not separated by 
a fimbriated channel. Forficiform pedicellariw present . . 5 . Luidia. 
b. Supero-marginal plates present. Adambulacral plates separated by a 
fimbriated channel, No forficiform pedicellarie present , ~ . Platasterias, 
Subfamily AsTRoPECTININ#, Sladen, 1887. 
Genus Craspidaster, n. gen. 
Archaster (pars), Miiller and Troschel, Monatsber. d. k. Akad. d. Wiss. Berlin, 1840, p. 104; System 
der Asteriden, 1842, p. 65. 
Rays five, tapering, subrigid. General form subdepressed and flat. 
Supero-marginal and infero-marginal plates largely developed, remarkably thick and 
