6 PROCEEDINGS OF THE NATIONAL MUSEUM. vol.64. 



Type locality. — Mororan, Hokkaido, Japan. Collected by D. S. 

 Jordan and J. O. Snyder. 



Type. — Will be deposited in the United States National Museum; 

 cotypes in zoological collection, Stanford University, and in the 

 British Museum (Natural History). 



Remarks. — Lysastrosoma is sufficiently close to Pycnopodia to be 

 included in the Pycnopodiinae. 



The structure of the crossed pedicellariae is strikingly similar ^ in 

 the two genera. In Lysastrosoma the large inferomarginal spinal 

 sheath envelopes both spines, but in Pycnopodia each spine has its 

 sheath with a distinct mass of pedicellariae. The difference in the 

 size of the mouth plates is, of course, due in part to the crowding 

 of the rays in Pycnopodia^ but not entirely, since some polybrachiate 

 forms — Ooronaster, for example — avoid extreme compression of the 

 oral plates. The line drawings show the essential difference in the 

 arrangement of marginal plates in specimens of approximately equal 

 size (figs. 1 and 4). 



EXPLANATION OF PLATES. 



Plate 1. 

 Lysastrosoma anthosticta. Abactinal view of type, enlarged. 



Plate 2. 



Lysastrosoma anthosticta. Actinal view of type, enlarged. 



2 The figures given by Verrill, Sballow-water Starfishes of the Noi-th Pacific Coast, etc., 

 1914, text fig. 2 ; pi. 74, flg. 6 ; pL 88, fig. 7c, for Pycnopodia are unlike any pedicellariae 

 I have seen in that species. Some of the figures suggest pedicellariae of Stylasterias 

 forreri. 



