182 THE VOYAGE OF H.M.S. CHALLENGER. 
are frequently pointed and channelled along their length, or gouge-shaped. The spinelets 
in the webbed fringe on the three attingent sides of the adambulacral plates are fewer 
in number, as also are the spinelets on the paxillee of the abactinal area (see Pl. XVIII. 
fig. 1). These, however, are characters which I regard as attributable to the smaller size. 
Localities. —Challenger Expedition : 
Hong Kong, 10 fathoms. 
Station 203. East of Panay Island (Philippine group). October 31, 1874. Lat. 11° 
6’ 0” N.; long. 123° 90” E. Depth 20 fathoms. Mud. Surface temperature 85°:0 Fahr. 
Other localities: Japan (Miller and Troschel) ; Banka Straits (Stockholm Museum) ; 
Singapore (von Martens). 
Remarks.—Miiller and Troschel’s type-specimen in Berlin from Japan, collected by 
Captain Wendt, which I have examined, conforms in all points—in so far as the dry 
specimen can be compared—with the form above described from Hong Kong. It is, 
however, somewhat smaller, measuring R= 41 mm.,r=11°5 mm. The thumb-like spine- 
let is present in the adambulacral armature. The thumb is also present in a specimen 
from Banka Straits preserved in the Stockholm collection. 
I have likewise seen the type of Mébius’s Stellaster sulcatus. It is unquestionably 
the same species. The two specimens are rather small, R=35 and 36 mm., with 
r=12 mm., in the example measured by me. This observer has noted? the peculiar 
bordering of spinelets on the marginal and actinal intermediate plates, also the granulate 
covering of these plates and the general character of the paxille. 
An example preserved in Copenhagen, which I have also studied, has been carefully 
described by Liitken,” who at the same time pointed out that Stellaster sulcatus, Mobius, 
was synonymous with Archaster hesperus. 
In the specimen at Leyden, seen by Miiller and Troschel, I find that the thumb-lke 
spine on the adambulacral plates is not so largely developed or so prominent as it some- 
times is, nevertheless it is present. The locality of this example is unknown ; it is simply 
stated in the System der Asteriden to have been collected by von Siebold. 
Genus Leptoptychaster, Smith. 
Leptychaster, Smith, Ann. and Mag. Nat. Hist., 1876, ser. 4, vol. xvii. p. 110. 
Leptoptychaster, Smith, Phil. Trans., Zool. Kerguelen Island, 1879, vol. clxviii. p. 278. 
The type of this well-marked genus was obtained off the island of Kerguelen during 
the sojourn of the British Expedition to observe the transit of Venus in 1875. The 
collection of Starfishes was described by Mr. E. A. Smith, who clearly diagnosed the pre- 
sent genus; and gave a figure of the species for the reception of which it was established. 
' Neue Seesterne des Hamburger und Kieler Museums, 1859, p. 11, Taf. iv. figs. 1 and 2 (Avhandl. a. d 
Gebiete Naturw. hrsg. v. d. naturwiss. Verein, Hamburg, Bd. iv. Abth. 2, 1860). 
) 
2 Videnskab. Medd. naturh. Foren. i Kjgbenhavn, 1864 (1865), p. 136. 
