416 THE VOYAGE OF H.M.S. CHALLENGER. 
Chorological Synopsis of the Species herein mentioned. 
| 
Ocean. | Range in Fathoms. Nature of the Sea-bottom. 
Metrodira subulata . A Eastern Archipelago. | 8 Coral mud. 
1. Metrodira subulata, Gray. 
Metrodira subulata, Gray, 1840, Ann. and Mag. Nat. Hist., vol. vi. p. 282. 
Scytaster subulatus, Miiller and Troschel, 1842, System der Asteriden, p. 36. 
Locality.—Station 186. In Torres Strait, off Cape York. ‘September 8, 1874. Lat. 
10° 30’ 0” S., long. 142° 18’ 0” E. Depth 8 fathoms. Coral mud. Surface tempera- 
ture 77°°2 Fahr. 
Family ZoROASTERID A, Sladen, 1888. 
The genus Zoroaster was originally classified by Sir Wyville Thomson" in the 
Asteriide. It was subsequently referred by Perrier’ to the family Pedicellasteride, 
established by him in 1884. In the following year, 1885, it was, however, removed by 
Perrier * into the new family Stichasteride. In my opinion Zoroaster and its allies are 
very far removed from Pedicellaster, and, although in some of their characters they 
approach much more nearly Stechaster, I consider that the details of their structure 
justify the establishment of an independent family. 
I include in this family the genera Zoroaster, Cnemidaster, and Pholidaster. 
Genus Zoroaster, Wyville Thomson. 
Zoroaster, Wyville Thomson, The Depths of the Sea, 1873, p. 154. 
Disk small. Rays long, narrow, tapering throughout, arched abactinally and with a 
more or less definite median keel, tumid actinally. Interbrachial arcs acute. 
Abactinal, marginal, and actinal intermediate plates arranged in regular longitudinal 
lines along the ray. Regular transverse series are also formed, the plates being corre- 
spondent and equal in length in each series as they proceed along the ray, excepting the 
plates in the median series, which are larger, The surface of all the plates is covered with 
small widely-spaced granules, upon which are articulated small, papilliform, skin-covered 
spinelets. A small robust conical spine may be borne on the plates of the median series, 
1 The Depths of the Sea, 1873, p. 154. 
? Nouv. Archives Mus. Hist. Nat., 2e Série, t. vi. p. 167 and p. 195. 
3 Ann. Sct. Nat. (Zool.), 1885, t. xix., art. No. 8, p. 15. 
