250 NEW STARFISHES AND OPHIURANS—VEBRILL. vol.xvii. 



of S. America, aud to P. tesselJatuSy from off" Cape of Good Hope, than is 

 indicated by Sladeu's descriptions. 



It ranges from 110 to 1,G08 fathoms, off our coast. 



PSEUDARCHASTER CONCINNUS, new species. 



A large, regularly stellate, five-rayed species, having a broad flat 

 disk and a rather thick margin with the interradial border regularly 

 incurved. Rays broad at the base tapering regularly to slender sub- 

 acute tips. Lesser to greater radius as 1 to 3.5. 



Abactinal area covered with regular hexagonal and rounded paxil- 

 liform groups, those in the center of the disk and aloug the middle 

 of the rays, decidedly larger than the rest, slightly convex, with a 

 central group of from 20 to 30 obtuse, slightly elevated granules or 

 papillte and a marginal series of from 20 to 30 smaller and more slender 

 divergent pax^illie. 



Upper marginal plates are nearly vertical and slightly convex and 

 encroach but little on the disk. They are much higher than long on 

 the margin of the disk, and are covered with rather large, rounded gran- 

 ules. Lower marginal plates nearly horizontal, confined largely to the 

 actinal surface, and thickly covered with acute, imbricated spines, those 

 on the middle largest. 



Actinal interradial area.s large, occupied by closely united plates, of 

 which the outlines are indistinct. I'^ach plate bears one to three or 

 more acute fusiform spines in the middle, and a marginal series of 

 much smaller and more slender spines of similar form or more clavate. 

 The adambulacral plates project inward nearly half across the furrow, 

 leaving deep angular notches between them. The furrow series of 

 adambulacral spines arise from the margins of the projecting portion of 

 the plate, and each angular group contains eight to ten rather slender, 

 moderately long, obtuse spines, of which the middle ones are a little the 

 longest. 



The largest si)eciinen, from station 270G, had, when dried, tlie radius 

 of the disk, 34 mm. ; of the rays, 105 to 110 mm. ; breadth of rays at base, 

 40 mm.; height or thickness of interradial margin, 12 mm.; height of 

 largest superior, marginal, interradial plates, 11 mm.; their length, 2.5 

 to 3 mm.; diameter of the large j)axillie of the median radial series, 

 3 mm.; diameter of madreporic plate, 2 mm. 



The central area of the disk is occupied by rather close set, roundish 

 parapaxilla:'. The anal pore is small but distinct, nearly central. 

 The madreporic plate is small, nearer to the center than the margin 

 (distance from the center, 12 mm. in the largest specimen). The ten 

 radial and interradial primary plates scarcely differ in size and form 

 from the adjacent plates. Three to five rows of large hexagonal 

 paxillae extend along the middle radial areas of the disk and bases of 

 the arms, becoming smaller and less regular beyond the middle of the 

 arm. On the disk these are bordered on each side by several rows of 



