134 IKVERTEBRATA. 



Some occasional and exceptional spines occur amongst some of 

 the undermentioned species of Cidaris, which are undistinguishable 

 from the Upware spines. But these latter are the proper type of 

 the species, and not exceptional, as is proved by the constancy of 

 their character in all the known specimens. I have not been able 

 therefore to identify them with any known species. 



G. vertidllata (Stoppain) differs in that its thorns are grouped 

 in verticals. In C. spinigera the spines are more slender, and are 

 usually curved (Cotteau), the thorns also being longer and more 

 spine-like. 



It is nearest to C. spinosa, Agassiz, of the Jura, Terr, a Chailles 

 at Fringeli, found also in the Jurassic of Normandy and N. 

 Germany. " Un espece tres voisine, mais cependant specifique- 

 ment differente, provenant de Fargile de Speeton, est figure'e dans 

 Phillips, Oeol. Yorkshire, t. IL, f. 3." This figure shews the thorns 

 arranged, somewhat irregularly, in zones. 



The thorny spines of C. muricata in the Hils Conglomerat vary 

 much as seen in the Gottingen Museum, but they are distinguished 

 from our Upware species by having the interspaces between the 

 thorns muricated. 



Some forms of the C. variabilis (Bunker and Koch) agree very 

 well with ours, but the spine is sharper, and we do not find any of 

 the typical forms of this species at Upware. Other thorny spines 

 occur in the Cretaceous of Rugen (Desor), and in the Kimmeridge 

 Clay of Ely (Woodwardian Museum). 



A single interambulacral plate in the Woodwardian Museum, 

 from Upware, may have belonged to the same Urchin. It does 

 not agree with Ooster's figure of wha-t he believes is the plate of 

 C. spinifera. It is transversely oblong, densely granulated, with 

 large areole, wide and rather prominent boss, with coarsely crenu- 

 lated summit. 



Localities. Upware, Brickhill, Farringdon (?), Godalming. 



CIDARIS ? sp. 



The pyramid of jaws (alveoli) of a large Urchin, measuring one 

 inch in height and breadth. 



Locality. Upware (Coll. Mr J. F. Walker). 



