54 Mr. F. A, Bather on Eocidaris and 



The feature seized on by Desor, tlie absence of a basal 

 terrace, is not enough to distinguish these species from 

 Echinocrinus (= ArchcBOcidaris) , especially when so few 

 plates are known. Still the general nature of the ornament, 

 at least in C. Icevispina, and more particularly the character 

 of the radicles, are enough to warrant the separation. The 

 radiole of C. Icevispina rather resembles those of Lepidocidaris 

 squamosa^ as I judge from excellent photographs kindly lent 

 me by Professor Jackson, but that species has slight extra- 

 Bcrobicular ornament. Without knowledge of larger portions 

 of the test, it would be quite unsafe to refer Cidaris Icevispina 

 to either Echinocrinus or Lepidtcidaris ; but there seems no 

 reason why it should not remain in the Lepidocidarida?, as 

 genotype of a distinct genus, Eocidaris Desor. 



Carboniferous Species referred to Eocidasis. 



The discussion of the American species at one time or 

 another referred to Eocidaris may safely be left to Professor 

 Jackson, who will, one hopes, at last provide a iigure of the 

 much-discussed E. drydenensis. The others are E. hlairi 

 Miller (1891, p. 73, pi. xii. ff. 1, 2) and E. hallianus Geinitz 

 (186G). 



Neither does it seem necessary to say more about Eocidaris 

 rossica and E. munsteriana, which have been dealt with by 

 Tornquist, Hesse, and others, and will receive further atten- 

 tion from Jackson. Both doubtless belong to Echinocriiius. 



Permian Species referred to Eocidaejs. 



For detailed information regarding C. keyserlingi we are 

 indebted mainly to K. Kolesch (1887), but also to Doederlein 

 (1887), E. Spandel (1898, pp. 33-37, pi. xiii. ff. 1-6), and 

 E. K. Hesse (1900, pp. 213, 214). Good specimens from 

 Possneck in the British Museum (E 1119, E1121) have 

 enabled me to check several of the statements made by these 

 authois. 



In supposing the shape to be that of an ordinary Cidaris 

 or Ilenucidaris, Spandel seems to be more correct than 

 Kolesch, who perhaps forgot to leave enough room for the 

 apical system. 



In assigning to a single interambulacral column six full 

 plates, Spandel is probably nearer the truth than Kolesch 

 with his seven plates, and certainly nearer than Doederlein 

 with his four or tive. 



Spandel, however, seems to think that there was at the 



