250 s. GOTO : 



Platten (^Yentrolateralplatten) eine paxilläre Fonn lial)en.' In other words, 

 the geniLS is erected on tlie strength of the imarmed marginals and large 

 actinal areas — jnst the features in -wliich LephjcMster differs from Astr'opeden, 

 for the size of the superomarginals has been shown to be variable within a 

 species, and not diagnostic of a genus. 



" The impossibihty of recognising a separate genus Parastropeden for 

 inermis and cmomahs is the fact that Lcptijchaster 2rro2yinqtms would have 

 to be ranked under Leptychaster on account of small superomarginals, L. 

 anomalvs, of com-se, under Parastropederi, L. j9nci}?cws probably under 

 Parastropeden, on account of the larger superomarginals, although it is a 

 close relative of L. ardiciis. To divide the genera on the presence or absence 

 of an anus would lead to the ranking of Parastropeden inermis and Leptych- 

 aster arcticus under one genus and the other forms under another, and 

 would necessitate ignoring the very characters upon which we base genera. 



" Consequently, although Parastropeden seemed fully warranted when 

 described, it seems best now to merge it with Leptychaster. 



" The genus Ghjphaster Verrtll based (without diagnosis) on L. anomalvs 

 seems to be sjTionymous with Parastropeden, which would therefore have 

 precedence if anomalvs constituted a separate genus. Since there are inter- 

 gi-ading forms with arcticus, I have no hesitation in saying that neither 

 Ghjphaster nor Parastropeden can be so diagnosed as to include Leptych- 

 aster propinqvus and exclude typical Leptychaster. 



" I liave examined two small specimens from the Sea of Ja^^an, collect- 

 ed by the Albatross in 1906. If the tiny si>ecimen from off Monterey is 

 certainly anomalvs, the si)ecies probably has a continuous distribution l)y 

 way of Bering Sea. It is of interest to note that the Japanese examples 

 are fairly typical. Both of them have epiproctal cones, and in one the tiny 

 anal pore is visible (in sunlight) with a strong glass." 



Tliis species is not contained in any of the collections mentioned at 

 the outset. 



