STARFISHES OF THE PHILIPPINE SEAS. 59 



following additional differences separate megaloplax from gracilis: 

 Eay shorter in megaloplax (R=5 r) ; dorsolateral edge of ray more 

 rounded; ray broader, with a decidedly broader paxillar area, which 

 tapers more evenly from the base toward tip, and despite their larger 

 size, there are more paxillae in a transverse row across ray than in 

 gracilis (at middle of ray, 28 in megaloplax^ 17 in gracilis) ; sub- 

 ambulacral spine more conspicuous in megaloplax. 



The example from station 5625 is remarkable from having only 

 two interradii normal as regards the odd marginal plates and the 

 odd double series of actinals leading therefrom to the mouth plates. 

 These two interradii are that of the madreporic body and the adja- 

 cent one to right (between bivium and trivium). One other inter- 

 radius has paired inferomarginals and superomarginals, and paired 

 double series of actinal intermediate plates. Another has an odd 

 superomarginal and paired inferomarginals and actinals. The fifth 

 has paired superomarginals and apparently paired inferomarginals, 

 but the odd plate is pushed to one side of the median interradial 

 line and a supernumerary plate is inserted in the ventral series a few 

 plates distant. The odd actinal double series is also crowded to one 

 side, but its inner end meets the combined mouth plates. The disk is 

 somewhat smaller than that of type, and the paxillae of disk a trifle 

 smaller. 



This abnormal specimen does not particularly suggest a hybrid, 

 with Goniopecten asiaticus. It is puzzling to account for the unsta- 

 bility of the generic characters, however. In one interradius the 

 specimen is Goniopecten^ in two it is Piionaster^ while in two others 

 it is a combination or mosaic of the two genera. 



Family ASTROPECTINIDAE Gray 1840, emended. 



Subfamily Craspidasterinae Fisher. 



Craspidasterinae Fishee, 1916a, p. 3. 



Diagnosis. — Resembling the Goniopectinidae in having a single 

 series of webbed peripheral spinelets on the marginal and actinal 

 plates, but differing in lacking the characteristic double serial ar- 

 rangement of the actinal intermediate plates, which are arranged 

 essentially as in the Astropectininae; in having patently double am- 

 pullae, and in the form of the hepatic coeca which arise from five 

 radial diverticula of the dorsal part of the stomach, as in Astro- 

 pecten. 



