571 



marginals; no intermarginals; adambulacral spinelets 



short, usually in 2 transverse series . annectens new subspecies. 



dd. Papular areas fairly large; spinelets unusually long, in 

 spaced fascicular groups; a long series of inter- 

 marginals; marginals not wider than long armed with 

 a cluster of comparatively long spinelets; adambulacral 

 spinelets unusually long in a zigzag transverse series. 



longispina new species. 



aa. Regularly 2 or more spinelets on the furrow face of the 

 adambulacral plates ; adambulacral spinelets numerous ; 

 rays flexible, 

 b. Abactinal and lateral pseudopaxillae small, evenly 

 spaced; papulae single, arranged in fairly regular ob- 

 lique transverse series on either side of the median 

 radial line (at least when viewed internally) polyacantha Fisher. 



bb. Plates small forming a sinuous irregular meswork 

 enclosing smaller, lower plates also more or less joined 

 in a close mesh between which emerge single papulae, 

 which do not form transverse oblique rows . clarki new species. 



Henricia leviuscula muUispina new subspecies. 



General form very similar to that of H. leviuscula but the abactinal 

 plates more compactly placed, smaller, and more numerous; the papular 

 areas smaller; the spinelets very numerous, delicate, longer than in 

 leviuscula^ and ending typically in 3 or 4 (sometimes more), slender very 

 sharp points or awns; adambulacral plates with numerous (25 — 50) 

 spinelets, and typically with 2 spinelets on the furrow face, beyond 

 middle of ray; proximally only 1. Rays 5; R 88 mm; r 15 mm; R 5,8 r; 

 breadth of ray at base 18 mm. 



Near Semisopochnoi Island, Aleutian Islands, 54 fathoms. Bottom, 

 broken shells, pebbles, sand. 



The most evident characters by which this form may be distin- 

 guished from leviuscula are the delicate abactinal and lateral spinelets 

 which end in several sharp points or awns , and the numerous adam- 

 bulacral spinelets, there being 3 or 4 on the furrow margin, sometimes 

 slightly to markedly compressed and spatulate, the rest decreasing in 

 size toward the outer part of plate. The plates are more closely placed 

 than in leviuscula^ the papular areas being much smaller than the plates. 

 The latter have a convex surface, bristling with delicate glassy spinelets 

 (40 — 60 or more) reminding one of Chaetaster. Marginal plates com- 

 pactly placed, conspicuous, in 2 regular series, the inferomarginals the 

 larger, and wider than long. A series of actinal intermediate plates 



