296 BULLETIN OF THE BUREAU OF FISHERIES. 



oblong, ami usually truncate; number of papilla 1 to each plate varying, and arrangement so compact 

 that if the prevalent slime is thoroughly cleaned off the outlines of the groups in the interradial areas 

 are clearly distinguishable; at outer end of mouth plates a few isolated papillae which resemble in 

 shape a flattened grain of corn attached by the small end. These groups of spinelets are considered 

 as pedicellarise by Danielssen and Koren in 11. jxil/iilus. In the present species the compact grouping 

 suggests pedicel larise, but I seriously doubt whether they serve any such purpose. 



Madreporic body small, broadly oval, situated a little to the outer side of a point midway between 

 center and margin of disk. Striatums coarse, radiating from center of larger (adcentral) end. 



Locality: Station 4387, off San I'iego, Cal. (longitude of Point Conception), 1,059 fins., mud. 



While the present species is undoubtedly a Bathybiaster in general facies, in the character and 

 armature of the marginal plates and actinal intermediate plates, yet in the armature of the adain- 

 bulacral and mouth plates it strongly resembles Pgilaster. The peculiar adambulacral spinelets 

 of B. lorijics Sladen (from off the west coast of South America near the entrance to the Straits of 

 Magellan) are not even suggested in this species. 



Genus DIPSACASTER Alcock. 

 Dipsacaster Alcock, Asiatic Soc. Bengal, LXII, 1S93, 17'J (no diagnosis) ; Ann. N. H. (fi) XI, 1893, 87 (/». i» ntagonalis Alcock). 



Dipsacaster exirnius, new species. 



Rays 5. R = 10cSmm.; r = 44 mm. R = 2.45r. Breadth of ray at base, 51 nun.; at middle of I!, 



40 nun. 



General form flattened, rays broad, leaf-like in shape, tapering gradually, but with an outwardly 

 curved contour, extremity bluntly pointed; interbrachial angles wide, abruptly rounded; abactinal 

 surface but slightly inflated, a slight depression mi interradial lines; actinal surface subplane, tube feet 

 large, with pointed tips. 



Abactinal paxillse very regularly arranged on rays in chevrons pointing toward center of disk, the 

 regularity continuing nearly to the center, but along median radial line a slight irregularity; each pax ilia 

 consisting of a high pedicel surmounted by a globular or elongate crown of very numerous, slender 

 spinelets sheathed in delicate membrane, the whole forming a dense glomerular tuft, the central 

 spinelets bluntly tipped, but those on the side uiucronate, less crowded, and usually extending in a 

 bristling arrangement down sides of pedicel for some distance. In a dried specimen the centrally 

 situated spinelets are much sharper, due to a shrinkage in the membraneous envelope. 



Marginal plates regular and massive; inferomarginals extending laterally beyond superomarginals 

 a distance nearly equal to the width of the latter, thus defining the contour of the body; exposed 

 surfaces of plates separated by remarkably deep fasciolar channels. Superomarginal plates, 32 in 

 number from median interradial line to extremity of ray, slightly wider than long, forming an arched 

 bevel to margin of paxillar area, and confined entirely to abactinal surface, even in the interbrachial 

 arc, where they are shortest and widest; exposed surface, which is slightly tumid, covered with 

 small polygonal granuliform spinelets along transverse median line, these rapidly becoming slenderer 

 at. margins of elevated ridge, and finally capillary in the fasciolar grooves. Nearly all the plates bear 

 a tubercular, strongly clavate, knobbed spinelet rather nearer the aboral edge than the center, with 

 occasionally 1 or 2 smaller companions. These do not extend far above the general level of the other 

 spinelets, except in one large specimen. Inferomarginal plates corresponding exactly in number and 

 position to superomarginals; specialized ridge of each plate very high, and tumid; plates forming 

 a broad border to actinal surface, and much wider than long; on lateral end of each plate, that por- 

 tion forming edge of ray, a transverse series of 4 to stout, tapering, sharp spinules, the uppermost 

 (or that next) longest, these spinules forming an armature on margin of ray; general covering of 

 plate consisting, on actinal surface, of ovate to oblong-lanceolate squamiform spinelets, which become 

 capillary and very sharp in the fasciolar channels; outer end of plate bristling with slenderer, 

 sharper, lancet-like spinelets, those on sides of the broad fasciolar grooves with excessively line, 

 mucronate tips. 



Adambulacral plates massive, with a curved furrow margin; armature consisting of (1) a furrow 

 series of 6 strongly compressed, round-tipped spines, usually standing at right angles to surface of 

 plate, and with their edges to the furrow, the 2 centrally situated longest (3.75mm. ) ami bluntest and 



