58 



Mr. F. A, Bather on EiKidaris and 



rayonnants " or '* radiiiren Vertiefungen/^ Kinj^ merely 

 said " Glenoid circles radiately crenulated/' words that refer 

 solely to what is here called the creiielate platform of the 

 boss, and in this respect there is no difference betveen the 

 German atid the British specimens. If the words of Kolesch 

 are due to an independent study of interambiilacrals from 

 the Magnesian Limestone, he may be referring to the fact 

 that the depressions between the crenellse are occasionally 

 prolonged faintly do^vn the slope of the boss. Such an 

 occurrence, however, is not uncommon in other allied species, 

 and has been observed by both Spandel and myself in 

 C. k<'yserhngi. What differences Lambert thought he could 

 see between these two species, does not appear in his writings : 

 we shall return to Permocidaris, which he defines as an 

 Archasocidarid, and it will then be clear that C. verneuiliana 

 can have nothin": to do with such a genus. 



Fijr. 2 



Ficr. 3. 



Mioeidaris keyserlinr/i. Two of the most perfectly preserved fragments 

 of interambulacra &om the Magnesian Limestone of Tunstall 

 Hill, CO. Durham, showini? the association and general shape of the 

 plates. In tig. 2 the scrobicules are confluent; in fig-. 3 they are 

 confluent above, but merely contiguous in the ambital region. 



The species described by King, though referred by him to 

 Archceocidaris in his text (1850, p. 53) and to Palcechinus in 

 the legend to his plate, is in fact a Cidarid. " The sub- 

 hexagonal form of the plates which . . . principally led^' him 

 " to regard it as an Archceocidaris " must be assigned to the 

 imperfection of his specimens. There are before me 11 

 fairly large fragments of interambulacra, each with two 

 column?, but none with more. The outer lateral margins of 



