118 CLARK: NEW GENERA OF ECHINODERMS 



arm bases; but within and beyond these the plates are small, irregularly 

 polygonal, and with no obvious arrangement. All of the actinal inter- 

 mediate plates are slightly tumid and are uniformly covered with 

 crowded granules; many bear pedicellariae, of which those on the 

 plates adjoining the adambulacrals are conspicuously larger than the 

 others; a plate in this series may bear as many as four pedicellariae. 

 At the oral angle of the interradial area there is usually a large odd 

 plate which may bear as many as six pedicellariae. 



The adambulacral plates are about as long as broad, becoming pro- 

 portionately longer distally; the furrow border is angular; the furrow 

 series consists of from 10 to 15 flattened spines, the outer flattened 

 parallel with, the inner transverse to, the furrow; within these there is 

 a bare area, followed by a row of from four to five prominent stout 

 spines, beyond which are numerous tubercles decreasing in size toward 

 the outer edge of the plate. Most of the adambulacral plates bear one, 

 proximally often two, large high pedicellariae on the inner part near the 

 proximal border. 



The mouth plates are small; each of them bears from 12 to 15 very 

 .stout flattened spines along the furrow, and a half dozen or more short 

 spines, either forming a single row along the suture line, or more ir- 

 regularly arranged, on the actinal surface. 



Mariaster differs markedly from Johannaster in the lack of regularity 

 in the arrangement of the actinal intermediate plates, in the absence 

 of spines on the same plates, and in several other important features. 

 It agrees more nearly with Ly Master and Circeaster (especially the for- 

 mer), showing its relationship in the character and arrangement of the 

 actinal intermediate plates, in the character of the armament of the 

 adambulacral plates, in the character and distribution of the pedicel- 

 lariae, in the form and size of the madreporite, and in other ways; it 

 differs most strikingly from these genera in having narrower and 

 longer arms on which the abactinal plates are not conspicuously larger 

 than those of the disk. 



The single species referable to this genus, Mariaster giganteus (Goto), 

 is known only from near Misaki, Sagami Bay, Japan, in from 160 to 

 1120 meters. Five specimens in all are known to have been collected, 

 four of which are in the museum of the Science College at Tokyo. 



Pseudonepanthia, new genus 



Genotype. — Pseudonepanthia Gotoi, new species. 



The characters of this new genus, which appears to be referable 

 to the family Asterinidae and the subfamily Asterininae, are included 

 in those of the type species, the description of which follows : 



Pseudonepanthia Gotoi, new species 

 Eight arms; R = 72mm.;r= 11 mm.; R: r = 6.5: 1; inferomarginals 111. 

 The rays are very long and narrow, almost circular in cross section, 

 evenly tapering to the tip; only three are of full size, the remainder 



