some Species referred to it. 65 



congeneric with those two species, and, if so, tlie name 

 Permocidaris will be a synonym of Miocidaris. 



Summary and Conclusions. 



The genotype of Eocidaris was not fixed by Desor (1856) 

 wlien he founded the genus. Subsequent authors have 

 removed from the genus all species referred to it by Desor 

 except Cidaris hevisjiina Sandb. and C. scrohicuiata Sandb., 

 which are the only two that agree with Desor's diagnosis. 

 But no author has yet selected a genotype. Therefore I 

 select C. Icevisjnna Sandb. as genotype. 



The original specimens of Eocidaris Icevispina are described 

 and figured, and the original of Sandberger's pi. xxxv. fio-. 2 a 

 (1855) is selected as type (lecto-holotype). The holotype of 

 Cidaris scrohicuiata is also redescribed and figured, and 

 considered congeneric with C. Icevispina. On this evidence 

 Eocidaris is provisionally maintained as an independent 

 genus of Archgeocidaridae ( = Lepidocidarid8ej. No other 

 species are placed in Eocidaris. 



Cidaris heyserlingi Geinitz, which has frequently been 

 referred to Eocidaris, is discussed, and fresh details of its 

 structure are given. Numerous topotypes of Cidaris ver- 

 neuiliana King are described and figured, and that species is 

 proved a synonym of C. heyserlingi. The evidence thus 

 adduced shows that these fossils belong to Miocidaris 

 Doederlein (1887). 



Miocidaris is rediagnosed and M. cassiani nom. nov. 

 {= Cidaris klipsteini Desor, non Marcou) taken as genotype. 

 The genus is distinguished from the recent Cidaris. 



Other species examined and referred to Miocidaris are 

 Cidaris suhcoronata Miinst., C. grandcBva Goldf. on the 

 evidence of Quenstedt's specimens (1875), and C. coceva 

 Qiienst. Others are alluded to. 



It follows that there is no necessity for Eotiaris Lambert, 

 founded to receive Miocidaris heyserlingi. 



It also follows that C/c/aris re/new/Zia?m King and G. coceva 

 Quenst. cannot belong to Permocidaris Lambert, a genus that 

 rests on the inadequately described Cidaris forhesiaua De Kon. 



EXPLANATION OF PLATE I. 



Eocidaris Icevispina (Sandberger). 



Fitj. 1. Lecto-holotype. Interambulacral, original of Sandberger, pi. 



xxxv. fig. 2 a. 

 Fi(j. 2. Interambulacral, original of Sandberger, pi. xxxv. fig. 2 b. 

 liy. 3. Interambulacral, original of Sandberger, pi. xxxv. fig. 2. 

 I'iy. 4. Radiole, proximal end, original of Sandberger, pi. xxxv. fig. 2d 



Ann. <D Mag. X. Hist. Ser. 8. Vol. iii. 5 



