EASTERN TROPICAL PACIFIC ASTEROIDEA. 95 
sacculatus FisHer, 1905. Ibid., p.316. Monterey Bay, Cala.,916fms. See Myxoderma. 
evermanni FisHerR, 1905. Ibid., p. 317. Between San Diego and’San Clemente Island, Cala., 500-507 
fms. 
magnificus Lupwic, 1905. Mem. M. C. Z., 32, p. 159. Gulf of Panama, 1,671 fms. 
nudus Lupwia, 1905. Tbid., p. 164. Gulf of California, 998 fms. 
hirsutus Lupwia, 1905. Ibid., p. 172. South of Acapulco, Mexico, 1,878 fms. 
longispinus Lupwtie, 1905. Ibid., p. 180. Eastern Tropical Pacific, 780—1,320 fms. 
spinulosus FisHeR, 1906. Bull. U.S. Fish Comm., 1903, p. 1102. Hawaiian Islands, 328-557 fms. 
bispinosus KoEBLER, 1909. Princesse-Alice Ech., p. 316. No locality given. 
adami Korner, 1909. Investigator Deep Sea Ast., p. 108. Bay of Bengal, 569 fms. 
platyacanthus H. L. CuarK, 1913. Bull. Amer. Mus. Nat. Hist., 32, p. 199. Off west coast of Lower 
California, 284 fms. 
ophiactis Fisher, 1916. Proc. Biol. Soc. Wash., 29, p.29. Gulf of Tomini, Celebes, 834 fms. 
maicroporus FisHer, 1916. Ibid., p. 30. Southwest of Amblan Island, Moluccas, 700 fms. 
carinatus philippinensis FisHEeR, 1916. Ibid., p. 30. Sibuko Bay, Borneo, 415 fms. 
macracantha H. L. CuarK, 1916. Endeavour Ech., p. 68. Great Australian Bight, 250-450 fms. 
actinocles FisHer, 1919. Ann. Mag. Nat. Hist., ser. 9, 3, p. 390. Aleutian Islands, 1,217 fms. 
evermanni mordax FisHer, 1919. Ibid., p. 390. Off Washington, 477 fms. 
Of the above species, tenuis and longispinus are based on very young speci- 
mens, in which the real specific characters are as yet undeveloped. It is useless 
to attempt to compare them with the adults of other species and they are there- 
fore omitted from the keys. Until adults are collected, accompanied by young 
and intermediate stages, these two names are of little service. Ludwig (1905. 
Mem. M. C. Z., 32, p. 177) has described another young Zoroaster but he re- 
frained from giving it a name. Koehler’s record (1908. Scotia Ech., p. 566) of 
tenuis from 1,742 fms. in the extreme South Atlantic Ocean merely shows that 
the genus ranges that far south. It is highly improbable that his specimen is 
conspecific with Sladen’s type of tenuis. Of course, bispinosus is only a slip 
of the pen for trispinosus. 
The remaining twenty-nine species include several groups which seem to be 
worthy of rank as distinct genera. First of these is Mammaster, proposed by 
Perrier in 1894 (Travailleur and Talisman Stell., p. 125) with Z. sigsbeei as the 
type. There is little doubt that the genus is very nearly related to Cnemidaster 
as that group now stands, thanks to Fisher’s investigations (1919. Bull. 100 U.S. 
N. M., p. 480-484). But I do not think it will ever be necessary “to merge 
the two genera” as Fisher suggests. For there is a rather striking character, 
hitherto apparently overlooked, which distinguishes Mammaster at once from 
any of the known species of Cnemidaster. This is given below in the key to 
genera and while it may not be of great morphological importance, it affects 
very evidently the general appearance of the disk. The ALBarross collections 
in the Philippines have revealed so well the growth-stages of Cnemidaster that 
we can now delimit that group of East Indian and Pacific species very well. 
