396 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



present very similar to those of O. sclerodermus^ and lastly because 

 near the extremity of the ray a rudimentary subambulacral spine or 

 granule makes its appearance. I recall that the species presents 

 several analogies to Linckia; it will not be surprising if the genera 

 actually intergrade. 



O. dubiosus resembles O. rhdbdotus Fisher (Hawaiian Islands) but 

 the latter has an actinal series of papular pores (8 series in all) and 

 large, spatulate subambulacral spines. 0. sclerodenrms Fisher and 

 0. tenellus Fisher (Hawaiian Islands) and O. tmnescens Koebler 

 (Aru Islands) are characterized by having no actinal papulae, but 

 all three are provided with well developed subambulacral spines. 

 In fact the absence of these in 0. dubiosus separates it from all 

 other Ophidiasters. 



I have never seen Ophidiaster pusiUus (Miiller and Troschel) , but 

 judging by Perrier's observations (1875, p. 128) that species resem- 

 bles a Linckia. Perrier states that in certain respects its adambula- 

 cral armature is intermediate between that of Linckia and Ophi- 

 diaster. The pedicellariae have a different form to those of duMosus, 

 being shorter and denticulate. 



Genus LEIASTER Peters. 



Leiaster Peteks, Monatsber. d. k. preuss, Akad. d. Wiss. Berlin, Apr. 1852, 

 p. 177. Type, L. coriaceus Peters. 



LEIASTER ANALOGUS Fisher. 



Plate 84, fig. 1 ; plate 95, fig. 7 ; plate 112, fig. 1. 

 Leiaster analogus Fisheb, 1913c, p. 215. 



Diagnosis. — Resembling L. coriaceus Peters in having grooved fur- 

 row spines, but differing in having longer, slenderer rays, numerous 

 pedicellariae, and the abactinal papulae in very definitely circum- 

 scribed areas. Differing from other species of Leiaster in having 

 channeled furrow spines. R=125 mm., r=:13.5 mm., R=9 r; breadth 

 of ray at base, 15 mm. Rays unequal, the longest 8.5-9 times as long 

 as width of ray at base. 



Desoi'iption. — General form closely resembling that of L. leachii. 

 Whole body overlaid by thick tough skin obscuring, unless dried, the 

 outlines of the 4-lobed, smooth plates, which are arranged in regu- 

 lar longitudinal and transverse series. There are 7 longitudinal 

 series of abactinal and marginal plates, and on either side 2 series of 

 smaller actinal intermediate plates, 11 series in all. Pedicellariae 

 very inconspicuous unless specimen is dry ; after drying they become 

 conspicuous. They are situated on the edge of the plates or on mar- 

 gin of papular areas, and each consists of 2 very slender spatulate 

 curved jaws which fit into smooth depressions of a roughly crescent- 

 shaped calcareous piece, embedded in the skin. One to 4 of these 



