372 Verrill, Notes on liadiata. 



OPHIUROIDEA. 

 Ophiactis virescens Liitken. 



Ophiactis virescens Lyman, Catal., p. 113 ; Verrill, Trans. Conn. Acad., i, p. 265. 



A few specimens of this species were found adhering among tlie 

 laminated scales of the pearl-oyster {Margaritophorafimhriata). 



ASTERIOIDEA. 



Linckia Unifascialis Gray {var. Mfascialis), Verrill, op. cit., p. 286. 



Dr. Gray considered this form a distinct species, but the specimens 

 that I have hithei-to seen do not aj)pear to wan-ant their separation 

 from tlie ordinary X, unifascialis, unless as a variety. Yet it may 

 eventually prove to l)e distinct when more and better specimens can 

 be examined. The only difference observed between them, is the 

 division of the lateral l)and of pores into two bands toward the base 

 of the rays, in the variety, while it is simple in the normal form. 



This variety ap})ears to be common at Cape 8t. Lucas and in the 

 Gulf of California, while at Panama it is very rare. 



Occurs from the Gulf of California to Zorritos, Peru. 



Nidorellia armata Gray. 



Pentaceros {Nidorellia) armatus Crray, Ann. and Mag. N. H.. vol. vi, p. 2TG, 1840 



Synopsis Starfishes in the Britisli Museum, p. 7, pL 14, 186G. 

 Oreaster armatus Miiller and Tr., Syst. Ast., p. 52, 1842. 

 Gouiodiscus conifer Mobius, N"eue Seesterne des Hamburg uud Ivieler Mus., p. 10, 



Trib. iii, fig. 5. 6, 1859. 

 Goniodiscus armatus Liitken, Vidensk. Meddel., 1859, p. 75. 

 Nidorellia armata Verrill, Trans. Conn. Acad., vol. i, p. 280. 

 Goniodiscus stella Verrill, op. cit., p. 284, (young), {uon Mobius). 



Additional specimens prove that our Goniodiscus stella is merely tlie 

 young of this species, while in the flat, spineless condition. The 

 characters of the young show the close affinity that this genus has 

 with Goniodiscus. 



Tliere is but one specimen from La Paz. Its range is from Guaya- 

 mas to Zorritos, Peru, 



AMPHIASTER, gen. nov. 



Disk moderately developed, flat above and below, Avith five broad, 

 triangular rays, and two well developed series of marginal plates. 

 Skeleton of the upper side formed by regular, polygonal, spine bear- 

 ing, tessellated plates, with pores between them ; on the lower side 

 composed of smaller granulated plates, each bearing a tubercle. 

 INIarginal plates granulated around the margin, smooth at center, or 



