from the Lias and Oolites. 163 



a powerful dental apparatus : three of the jaws are very promi- 

 nent ; the external surface of each is strengthened by three pro- 

 minent ridges ; the teeth are large, but are fractured. As the 

 under surface of the test only is shown, we are unable to describe 

 the ovarial disc and the dorsal surface thereof. 



Affinities and differences. — This Urchin belongs to the same 

 group as C. Fowleri and C. maxima, Goldf. It resembles the 

 former in the form and structure of both areas, and in the gra- 

 dual development of the primary tubercles from the mouth 

 upwards. It is distinguished from that species, however, by the 

 greater size and uniform perforation of the miliary tubercles, but 

 above all by the form and structure of the primary spines. 

 Having ascertained that our conjecture * relative to the spines 

 of C. Fowleri is correct, from having seen a specimen recently 

 found with some spines attached to it, we can speak positively 

 upon this point. 



Locality and stratiyraphical range. — Found by Mr. G. E. 

 Gavey, C.E., in the upper shale beds of the Lower Lias at 

 Mickleton Tunnel near Chipping Campden. It was associated 

 with Pentacrinus Goldfussii, Wright, Ophioderma Gaveyi, Wright, 

 Uraster Gaveyi, Forbes, and Ammonites planicosta, Sow. 



History. — Isolated plates of this species have been found in 

 beds of the same geological horizon in other localities of the 

 county of Gloucester, but the specimen before us is the only 

 one from which the anatomy of the Urchin could be made out. 

 We dedicate this species to Prof. Milne-Edwards, of the Museum 

 of Natural History at the Jardin des Plantes, Paris, as a tribute 

 of gratitude for the pleasure and profit derived from the study of 

 his admirable monograph on British Fossil Corals. 



Cidaris Bouchardii, Wright. PI. XI. fig. 2, c-c. 



Test circulai', depressed ; ambulacral areas narrow and flexuous ; 

 interambulacral areas with two rows of primary tubercles, 5-6 

 in each row ; the areolas of the small mammillary eminences 

 deeply excavated, and surrounded by an elevated ridge, on 

 which a distinct circle of granules for each areolar space is 

 disposed. 



Dimensions of the largest specimen. Height ^^ths of an incbj, 

 transverse diameter 1 inch and gijths. 



Dimensions of a moderate-sized specimen. Height ^^ths of 

 an inch, transverse diameter 1 inch and j^ths. 



Description. — It was for some time doubted whether the young 

 forms of this Urchin were not the C. elegans, Goldf., but a com- 



* Annals of Nat. Hist. Oct. 1851. 



11* 



