574 



to 8 slender spinelets considerably longer than the height of tabulum. 

 Papulae single. Inferomarginal paxillae, subcircular, only very slightly 

 compressed, two to every three adambulacral plates, and crowned by 5 

 to 12 delicate spinelets, longer than the pedicel and denticulate at tip. 



Solaster hypothrissiis new species. 



Similar in general appearance and structure to S. borealis^ but 

 differing in having a row of 5 to 7 prominent superoral spines parallel 

 to the median suture, in having a maximum of 6 long actinal adam- 

 bulacral spines instead of 4 or less, and in having the abactinal pseudo- 

 paxillae slightly higher, with 7 to 11 (instead of 3 or 4) spinelets which 

 are blunter than in horealis and end in several points, not in an attenuate 

 denticulate tip. Rays 10 or 11; E, 3 + r. 



South of Shumagin Islands, Alaska, 625 fathoms. Bottom, green 

 mud. 



Lopkaster fiwcilliger vexator new subspecies. 



Similar to L. furcilliger Fisher but with larger disk, thicker rays, 

 much stouter paxillae , both abactinal and marginal , and with stouter 

 abactinal spinelets (having 6 to 10 little prongs instead of 2 to 4), heavier 

 adambulacral spines and more closely placed adambulacral plates. 

 Perhaps intermediate between L. f urei fer and L. furcilliger. R 89 mm; 

 r 27 mm; R 3,3 r; breadth of ray at base 30 mm. 



Off Pt. Arena, northern California, 75 fathoms. Bottom, fine sand. 



This curious form may ultimately be found to intergrade with L. 

 furcifer of the Arctic Ocean and North Atlantic. Vexator differs from 

 typical furcifer (which apparently does not occur in the North Pacific, 

 or Bering Sea) in having a more open abactinal skeleton with con- 

 sequently more widely spaced paxillae, higher paxillae with longer 

 spinelets, much smaller actinal intermediate areas with fewer actinal 

 paxillae (about as in furcilliger) and longer adambulacral spines. If 

 equal sized specimens of the 2 forms are compared L. furcifer is seen 

 to have wide, rounded, interbrachial arcs which merge gradually into 

 the ray. Vexator has a smaller disk, never rounded interbrachial arcs, 

 but acute angles, the rays being sometimes swollen at the base so that 

 the marginal and adjacent abactinal paxillae of the 2 rays interlock. 

 The difference in the abactinal skeleton is parallel to that of Solaster 

 [Crossaster] squamatus and 8. papiMsus. 



Sarkaster Ludwig is not separable from Lopkaster, the type S. 

 validus being doubtfully distinct from my L. furcilliger. Besides, Lo- 

 phaster has actinal intermediate plates on the ray. L. vexator forms a 

 perfect link between the extremes L. furcilliger and L. furcifer. 



