ASTEROIDEA 79 



6 mm. in diameter, fragments of an encrusting bryozoan, a gastropod shell, delicate 

 membranous worm tubes, and a sea-urchin spine, possibly Austrocidaris ccmalicidata 

 (A. Agassiz). Treatment of the mud with sodium hypochlorite indicates a large percentage 

 of organic material. 



Family ASTROPECTINIDAE Gray 



Genus Leptychaster Smith 



Leptychaster Smith, Ann. Mag. Nat. Hist., Ser. 4, xvii, 1876, p. no. Type L. kerguelenensis Smith. 

 Leptoptychaster Smith, Philos. Trans. Roy. Soc, Zool. Kerguelen Island, CLXVUI, 1879, p. 278. 



Emendation of Leptychaster. 

 Parastropecteit Ludwig, Mem. Miis. Conip. Zool., xxxn, 1905, p. 76. Type P. inermis Ludwig. 

 Glyphaster Verrill, Amer. Nat., XLUI, 1909, p. 553. Type Leptychaster anomalies Fisher. — 1914, 



P- 327- 

 Priamaster Koehler, 1912, p. 92. Type P. magnificiis Koehler. 



Trophodisciis Fisher, 1917, p. 367. Type T. almus Fisher. 



New information on the structure of LeptvcJwster kerguelenefisis makes it desirable to 

 review the north Pacific species referred to Leptychaster. These are L. arcticns (found 

 also in the north Atlantic), L.pacificiis Fisher, L. propinqims Fisher, L. anomaliis Fisher. ^ 

 When the accounts of these species were written no information was available on the 

 distribution of the gonads in the type of the genus, nor had I seen a specimen of 

 kerguelenensis. In the description of Trophodisciis olmus, the distribution of gonads in 

 4 species of Leptychaster is stated as follows (Fisher, igiyw, p. 371) : " In four species of 

 the genus Leptychaster which I have been able to examine, the testes differ in distribu- 

 tion from the ovaries. In L. arcticus, L. pacifictis, L. propinqims and L. anomaliis (the 

 last three being North Pacific species) the ovaries are in a single tuft close to the inter- 

 radial septum — a pair, thus, in each interbrachium. In some specimens the branches 

 may extend far along the ray, but they are attached in only one place, as stated above. 

 In the male the gonads form a series of independent tufts of tubules, parallel with the 

 margin, and distributed for a third to nearly a half the length of ray, according to the 

 size of the specimen. The distribution of the testes in the above species of Leptychaster 

 is therefore similar to the distribution of both ovaries and testes in Trophodisciis, 

 Dipsacaster, Ctenopleiira, Tethyaster, Thrissacanthias, and other genera. This condition 

 of the gonads is apparently characteristic of the genus Leptychaster, although of course 

 it will doubtless be found to be true of other genera. The reason I did not discover this 

 when working up my North Pacific Asteroidea, Part I, was the fact that I dissected then 

 only a single example of each species, which happened in each case to be a female. 

 Recently, at the United States Museum, I found ' serial gonads ' in a specimen of L. 

 arcticus from station 21, Cashes Ledge. A specimen from station 4779 (North Pacific) 

 has serial gonads and is a male, while a female from station 5047 has strictly interradial, 

 non-serial, gonads. 



1 These species are described and figured in Fisher (191 1), where a definition of Leptychaster is given, 

 based on the northern species only. The statement in regard to distribution of gonads is erroneous, as ex- 

 plained below. 



