Manchester Memoirs ; Vol. Ixii. (191 7) 91 



stress. A more specialized form exhibiting rotundity is Cristel- 

 laria saulcyi d'Orbigny (d'O. 1839. F.I.C. p. 126. pi. III. figs. 

 7-9). D'Orbigny's figure agrees with Halkyard's types except 

 for the smaller number of chambers in the produced series. 

 Goes (G. 1894, A.S.F. p. 63, pi. XI, figs. 625, 626,) illustrates 

 under d'Orbigny's specific name elongate specimens comparable 

 in every respect with Halkyard's fossils.) 



211. Cristellaria bononiensis, Berthelin. 



Cristellaria bononiensis, Berthelin, 1880, Mem. Soc. Geol. 



France, [3], vol. 1, p. 55 pi. Ill, (XXVI), fig. 23a-c. 

 C. bononiensis, Chapman, 1894, Journ. Roy. Micr. Soc. p. 652, 



pi. X, fig. 9a, b. 



Extremely rare. Only one small specimen found in the 

 whole of the Gatherings. 



(The single specimen is not very satisfactory as compared 

 with Berthelin's figure, being too compressed and vaginuline. 

 It might equally well have been allotted to an elongate type 

 of C. tricarinella, Reuss.) 



212. Cristellaria acutauricularis, (Fichtel & Moll.) 



Nautilus acutauricularis, Fichtel & Moll, 1798, Test. Micr., p. 



102, pi. XVIII, figs. g-i. 

 Cristellaria acutauricularis, Brady, 1884, Chall. Rep., p. 543, 



pi. CXIV, fig. 17a, b. 



Rare and small. 



213. Cristellaria triangularis, d'Orbigny. 



Cristellaria triangularis, d'Orb., 1840, Mem. Soc. Geol. ; 



France, [1], vol. IV, p. 27, pi. II, figs. 21-22. 

 C. triangularis, Chapman, 1894, Journ. Roy. Micr. Soc, p. 651, 



pi. X, fig. 3a, b. 



Very rare. Can hardly be distinguished from C. italica, 

 (Deir.) It is convenient to separate the stout, broad forms, with 

 rounded angles from the more acutely angled and neater built 

 shells, which latter may be grouped under C . italica. No line 

 of demarcation can be drawn between the two varieties, one 

 merging into the other. 



(This is merely a passage form between C. acutauricularis 

 and C . italica. hardly worth separating from the latter.) 



