PLATE III. 



Fig. 



1. Ammonites blagdeni, J. Sowerby ; front view of specimen, Brit, Mus. no. 43908. 



2. Ammonites banhsii, J. Sowerby; front view of specimen, Brit. Mns. no. 43910. 



■Ml 



„ / 



Side view, nat. size. 



Inner whorls, enlarged. 



Portion of outer whorl, enlarged. 



Ammonites sowerbii, J. Sowerby, Min. Conch., vol. ii, p. 235, 1818, pi. ccxiii. 



[Bristol Museum.] 



" Specific Characters. — Discoid, carinated, with about eight spiniform tubercles 

 upon each whorl; keel defined, entire; aperture elliptical. Var. /3 aperture 

 circular, keel sometimes impressed. 



" Volutions about four, the inner ones concealed to the bases of the tubercles ; 

 the outer part of the volutions has many gentle undulations ; the inner part is 

 even, except that the base of each tubercle is extended towards the centre in an 

 obtuse ridge. The keel nearly separated from the body of the shell ; it is round 

 and entire. 



" In var. (3 the ridges from the bases of the tubercles are more prominent, and 

 the keel sometimes so far sunk as to have a furrow on each side of it. The inner 

 whorls of var. a appear to be more gibbose than the outer ones. 



" Mr. Miller considers the shell figured as one of his rarest specimens ; his 

 collection has also to boast of several smaller specimens, belonging to var. )3, which 

 vary in the gibbosity of the whorls ; they were all found at Dundry, in the Inferior 

 Oolite." 



