ASTEROIDEA 229 



crossed pedicellariae. These are present in an example of A^. bongraini having R 17 mm., 

 and in one of stolophora as small as 6-5 mm., so that age alone cannot account for their 

 absence. It may well be that they do not occur in some of the less specialized species of 



the genus. 



Genus Psalidaster nov. 



Diagnosis. Superficially resembling Saliasterias Koehler, but differing in having 

 large, crossed pedicellariae of Notasterias type, abactinal and marginal spines single, the 

 latter (surrounded by rosettes of crossed pedicellariae) forming two prominent lateral 

 series. Abactinal and intermarginal papulae; no actinal plates or papulae; adambulacral 

 plates diplacanthid, sporadically monacanthid and triplacanthid ; actinostome small, 

 mouth-plates small, adoral carina, long, narrow (5 or 6 plates) ; ambulacral furrow not 

 abnormally wide ; tube-feet slender, four ranked ; abactinal skeleton proximally very 

 irregularly reticulate, weak, disintegrated distally into separated small primary plates; 

 gonopores conspicuous, two to each constricted actinal interradial area. 



Type Ps. mordax sp.nov. 



Remarks. This new polybrachiate type cannot be confused with either Saliasterias 

 Koehler or Cryptasterias Verrill, since its crossed pedicellariae, nearly i mm. long, have 

 a highly characteristic form totally unlike the very small conventional pedicellariae of the 

 above named genera. This is rather a fortunate circumstance for the abactinal skeleton, 

 like that of so many Antarctic Asteriidae, is weak, reticulated, and without any special 

 clues to relationship ; while the mostly monacanthid marginals are also without outstand- 

 ing characteristics. The ovaries are small with large eggs, as in Cryptasterias, and open 

 ventrally. The skin, though soft and finely wrinkled, is not of the thick pustulate type 

 characteristic of Cryptasterias. 



The crossed pedicellariae resemble those of Notasterias in having a broad base for the 

 accommodation of heavier muscles, the jaws being swollen, with a large cavity. The 

 constricted distal end of the jaw is produced into two principal teeth which interlock 

 with those of the other jaw, instead of crossing. The suppression of one tooth would 

 produce a pedicellaria closely similar to those which predominate on the inferomarginal 

 and actinal spines of Notasterias armata (compare Fig. J, 46 with Fig. K, 2/, 2g). 



As to the place of this genus in the system, I believe that it may be regarded as allied 

 to Coscinasteriinae rather than to typical Asteriinae such as Diplasterias. 



Psalidaster mordax sp.nov. 

 (Fig. K, 2-2g, 3-36; Plate XVIII, figs, i, 2) 

 Diagnosis. Rays ii ; R 135 mm., r 27 mm., br 15-16 mm. Paratype R no mm., 

 r 23 mm., br 12 mm. Rays flexible, slender, with evenly convex pliant abactinal surface 

 uniformly beset with short soft papillae representing small spinelets, their associated 

 crossed pedicellariae and smaller interspersed papulae; abactinal skin soft, not thick, 

 not thrown into heavy welts, although finely wrinkled; marginal spines larger than 

 abactinal, in two regular longiseries, carrying rosettes of pedicellariae ; no actinal plates ; 



