Manchester Memoirs, Vol. Ixii. (19 17) 95 



(This appears to be nothing more than a compressed and 

 depauperate form of C. cultrata. Halkyard's specimens are 

 less pauperate than Hantken's figure suggests.) 



225. Cristellaria orbicularis (d'Orbigny.) 



Robulina orbicularis, d'Orbigny, 1826, Ann. Sci. Nat., vol. 



VII, p. 288, pi. VI, figs. 8-9. 

 Cristellaria orbicularis, Brady, 1884, Chall. Rep., vol. IX, 



p. 549, pi. LXIX, fig. 17. 



Very rare. Found only in the sample of clay brought home 

 in April, 1893, an ^ strangely absent from the larger quantities 

 of Marl collected at later times. 



226. Cristellaria wetherellii (Rupert Jones.) 



Marginulina w ether ellii, Jones, 1854, Morris Catal. Brit. Fossils, 



ed. 2, p. 37. 

 Cristellaria wetherellii, Brady, 1884, Chall. Rep., vol. IX, 



P- 537, Pi- CXIV, fig. 14. 



The species is frequent in nearly all the Gatherings, but is 

 best developed and most typical at the base of the Marl. In 

 the upper beds the examples are short and delicate in growth, 

 the surface ornamentation is not strong and almost every in- 

 dividual is provided with a thin dorsal keel. Traces of this last 

 feature are also to be found in the more typical specimens. 



(This is a fine series of specimens but none of them can be 

 considered as typical as compared with the familiar London 

 Clay types. (S. & C. 1885, etc. M.L.C. p. 652, pi. XV, fig. 

 18.) The Biarritz specimens are all short, broad, and except 

 for the somewhat turgid cross-section are much more nearly 

 allied to Brady's C. gemmata (Chall. Rep. p. 554, pi. LXXI, 

 figs. 6, 7.) than to C. wetherellii. In a few of the Biarritz speci- 

 mens there is a distinct tendency to dimorphic growth, the final 

 chamber being globular, and in one case separated by a short 

 neck from the penultimate chamber.) 



227. Cristellaria asperula, Giimbel. 

 PI. V. figs. 10, 11. 



Cristellaria asperula, Giimbel, 1868, (70). Abh. m.-ph. CI. k. 

 bayer. Ak. Wiss., vol. X., no description, pi. I, fig. 65a, b. 



C. asperula is an elongate, rectilinear, and compressed form 

 allied to C. wetherellii from which it is easily separated in the 

 Biarritz Gatherings, there being found no intermediate links. 

 It is not rare. 



