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PROCEEDINGS OF THE NATIONAL MUSEUM 



VOL. 81 



This new species seems to agree closely with Rhcibdocalyptus 

 australis Topsent in outer appearance and in essential characters of 

 spiciilation, but differs from it in three respects: In our species (1) 

 the surface of the prostal paratropal pentactins is smooth, except 

 at the end, instead of microtuberculated over the surface; (2) oxy- 

 hexasters consist of three kinds and usually have smooth or slightly 

 rough terminals; (3) the cliscoctaster has four to six terminals to 

 each principal, instead of three to four. 



RHABDOCALYPTUS HETERASTER, new species 



FiGXJBE 15 ; Plate 6, Figure 6 



The two complete specimens of this species were collected from 

 the Station 4770 (Bowers Bank, Bering Sea, 247 fathoms). Both of 



FiGDRB 15. — Rhabdocalyptus heteraster, new species : a, Gastral liexactin, X 225 ; 

 6, oxyhexaster (form B), X 270; c, oxyhexaster (form B), X 270; d, oxyhexaster 

 (form C), X 270; e, oxyhexastei- (form A), X 270; f, oxyhexaster (form C) ; 

 X 270 ; g, hexactinic form, X 270 ; li, hexactinic form, x 270 ; i, hemihexactinic 

 form, X 270 ; j, hemihexactinic form, X 270 ; k, discoctaster, X 270 ; I, dis- 

 coctaster, X 180 ; m, microdiscohexaster, X 270 



them are fairly thin-walled, subglobular, and purselike in form, and 

 are without a specially formed attachment at the base. In the 

 larger one (holotype, U.S.N.M. No. 22052) the total height is 85 mm 



