ASTEROIDEA 169 



no papulae between the inferomarginah and actinals, nor between the latter and the adam- 

 bulacrals. If the absence of actinal papulae is constant in specimens from Marion, 

 Prince Edward, and the Crozets, then simplex may be readily distinguished from 

 pagenstecheri in which there are actinal papulae even in specimens having R only 6 mm. 



Sladen has recorded simplex from Tristan da Cunha where the ' Discovery ' secured a 

 tiny specimen oi pagenstecheri. It would be an easy matter to confuse the two forms for 

 they are not distinguishable on spine characters alone. Since Sladen describes abactinal 

 and intermarginal papulae, but no actinal papulae, it seems almost certain that he had in 

 hand simplex and not pagetistecheri. 



Distribution. Prince Edward Island, Marion Island, Crozet Islands, Tristan da 

 Cunha, 50-150 fathoms. 



Henricia diffidens (Koehler) 

 Echinastcr diffidens Koehler, 1923, p. 58, pi. 8, figs, i, 2; pi. 9, figs. 9, 10. 



St. WS 840. 53° 52' S, 61° 49' W, 368-463 m., I specimen. 



St. WS 871. 53° 16' S, 64° 12' W, 336-341 m., 3 specimens. 



The largest specimen, from WS 840, measures R 17 mm., r 5-5 mm., br 6-5 mm. 

 The spines are somewhat longer than those of Koehler's specimens, particularly the 

 types from Graham Land, indicating the possible existence of a different race on the 



Falkland Plateau. 



It is not evident why Koehler placed this species in Echinaster, as it is of the general 

 habit of Henricia, and very small specimens greatly resemble equal sized H. pagen- 

 stecheri but have more numerous, longer abactinal spines, fewer and less obvious actinal 

 papulae. In the largest specimen the true actinal papulae appear at about the end of the 

 proximal third of furrow (measured from mouth) at about the point where the actinal 

 plates end. From this point to end of ray the spaced papulae lie between the infero- 

 marginal and adambulacral plates. Proximal to that point actinal papulae do not 

 regularly occur. 



H. diffidens greatly resembles two north Pacific species : H. asthenactis Fisher^ and H. 



longispina Fisher.^ 



At St. WS 871 was taken also one specimen of H. stiideri. 



Type locality. Graham Land (Swedish Antarctic Expedition, St. 5) 64° 20' S, 

 56° 38' W, 150 m., sand and gravel. 



Distribution. Graham Land, South Georgia, Falkland Plateau, 75-463 m. 



1 Fisher, 191 1, p. 297, pi. 77, fig. i ; pi. m, figs. 4, 4a. Vicinity of Santa Barbara Island, California, to 

 Bering Sea, 178-682 fathoms. 



- Fisher, 191 1, p. 299, pi. 76, figs, i, 2; pi. iii, figs. 3, 3a. Vancouver Island to southern Alaska, 41-134 

 fathoms. A race of longispina occurs near Attu, Aleutian Islands, 135 fathoms {H. longispina aleutica, 

 p. 300, pi. 77, fig. 2). 



