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 attingeut sides of the adambulacral plates are fewer 

 in number, as also are the spinelets on the paxillae of the abactinal area (see PI. 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° 9' 0" E. Depth 20 fathoms. Mud. Surface temperature 85°-0 Fahr. 



Other localities : Japan (Miiller 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 = ll - 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 Mobius'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 1 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 paxillae. 



An example preserved in Copenhagen, which I have also studied, has been carefully 

 described by Liitken, 2 who at the same time pointed out that Stellaster sulcatus, Mobius, 

 was synonymous with Ar chaster hesperus. 



In the specimen at Leyden, seen by Miiller and Troschel, I find that the thumb-like 

 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 Leptopty chaster, Smith. 



Lepty chaster, Smith, Ann. and Mag. Nat. Hist., 1876, ser. 4, vol. xvii. p. 110. 

 Leptoptychaster, Smith, Phil. Trans., Zool. Kerguelen Island, 1879, vol. clxviiL 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. 



1 Neue Seesterne des Hamburger und Kieler Museums, 1859, p. 11, Taf. iv. figs. 1 and 2 (Abhandl. a. d 

 Gebiete Naturw. hrsg. v. d, natunciss. Verein, Hamburg, Ed. iv. Abth. 2, 1860). 



2 Videnskdb. Medd. naturh. Foren. i Kj<pbenhavn, 1864 (1865), p. 136. 



