ASTEROIDEA OF NORTH PACIFIC AND ADJACENT WATERS— FISHER 131 



Diagnosis.— Nonfissiparous, five to seven rayed Coscinasteriinae with mona- 

 canthid adambulacral plates, pedicellariae on only the outer of the two inferomarginal 

 spines, one series of spiniferous actinal plates, and a thick tough skin covering the 

 skeleton, of which the dorsolateral portion is irregularly reticulated; the papular 

 areas equivalent to three or four longiseries, but only the lateralmost regular. Crossed 

 pedicellariae small, round tipped, without any enlarged terminal teeth; straight, 

 pedicellariae abundant, large, broadly lanceolate, with rather compressed denti- 

 culate jaws; odontophore with two distinct pits on the outer (septal) margin. 



West coast of Chile. 



Only one species is known, M. gelatinosus, five to seven rayed, which reaches a 

 diameter of 500 68 mm. 



Verrill (1914, p. 357) records another unnamed species with five rays "supposed 

 to be from the Society Islands (No. 1427, Mus. Comp. Zool.)." I have examined 

 this specimen which is Marthasterias glacialis, of which there is a large series in the 

 Museum of Comparative Zoology. It is not from the Society Islands. 



Although this genus bears a considerable resemblance to Marthasterias, it has 

 very different crossed pedicellariae and an unusual sort of odontophore. It is prob- 

 ably much closer to Astrostole. 



Genus AUSTRALIASTER Fisher 



Plate 42, Figures 5, 5a 



Auslraliaster Fisher, Ann. Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 253. Type CoscinasUrias 

 dubia Clark (Tasmania). 



Diagnosis. — Nonfissiparous, five-rayed, Coscinasteriinae with diplacanthid 

 adambulacral plates, pedicellariae on both inferomarginal spines, a well-developed 

 series of spiniferous actinal plates (without spine pedicellariae) and very small 

 crossed pedicellariae without enlarged lateral terminal teeth. Dorsolateral region 

 relatively broad, with irregular skeleton and, in type, few irregularly scattered 

 prominent spines; each carinal and superomarginal not regularly spiniferous — usually 

 only the alternate plates (which are sporadically diplacanthid); two pairs of contig- 

 uous postoral adambulacral plates; straight pedicellariae slender, lanceolate. 



Australia, Tasmania. 



The only known species is the type." 



Genus LETHASTERIAS Fisher 



Lethasterias Fisher, Ann. and Mag. Nat. Hist., ser. 9, vol. 12, 1923, p. 258. Type Astcrias 

 nanimensis Verrill. 

 Diagnosis.— Asteriidae differing from Distolasterias in having very numerous 

 and irregularly arranged dorsolateral plates, and crossed pedicellariae without a 

 conspicuously enlarged tooth on each side of the end of the jaw; odontophore with 

 two pits. Carinal and superomarginal plates small, four-lobed, strongly imbricated, 

 all spiniferous; superomarginal plates smooth, without trace of a specialized area of 

 hyaline beads; dorsolateral plates unusually numerous, without well-defined order 

 in arrangement, and with small intervening papular areas; two inferomarginal 



"Clark, Echinoderms of Peru. Bull. Mus. Comp. Zool., vol. 52, 1910, p. 337. 



•' Clark, H. L. Mem. Austr. Mus., vol. 4, pt. 11, 1909, p. 532, pi. 49. figs. 3, 4; pi. 50. Report on BMrUUm, etc., of the En- 

 deavour," 1916, p. 73, pi. 30, figs. 1, 2. 



