404 Messrs. Foord and Crick on new and 



1859. Nautilus triangularis, Pictet & Caurpiche, Description des Fos- 



siles du Terrain Cretace des Environs de Sainte-Croix (Paleontologie 



Suisse), ser. ii. pt. i. pp. 141, 149. 

 1861. Nautilus triangularis, R.eynes, Etudes sur le Synchronisme et la 



Delimitation des Terr.-Cretaces du Sud-Est de la France, p. 41. 

 1866. Nautilus triangularis, Beltremieux, Faune Fossile du Departe- 



ment de la Charente-Inf6rieure, pp. 43, 80. 



Sp. char. Shell compressed, smooth, with the periphery 

 alternately rounded and sharply angular ; umbilicus closed ; 

 section triangular, the sides very slightly rounded, deeply 

 emarginated by the preceding whorl. Septa considerably 

 curved upon the sides, and projecting forwards upon the 

 peripheral angle, slightly bent backwards in the umbilicus. 

 According to d'Orbigny the siphuncle is situated below the 

 centre, not far from the ventral border. Test unknown. 



Remarks. This species is readily distinguished from 

 Nautilus Fleuriausianus, d'Orbigny, as figured and described 

 in the ' Pal. Franc,.' (Terr. OCt. vol. i. p. 82, 1840, pi. xv.) 

 by its sharply angular periphery at different stages of growth. 

 D'Orbigny in his ' Prodrome ' (vol. ii. 1850, p. 145) makes 

 his Nautilus Fleuriausianus a synonym of the present species, 

 but he gives no reason for so doing, and we have no evi- 

 dence to show that N. Fleuriausianus underwent the same 

 changes of form as those noticed in N. triangularis. These 

 remarkable changes were pointed out by M. Ed. Gueranger 

 in a paper read before the Geological Society of France (Bull, 

 ser. ii. vol. vii. 1850, p. 803), and he thus described them : — 

 " Un caractere particulier et inedit est d'avoir le dos de la 

 spire alternativement anguleux ou en carene, et parfaitement 

 arrondi ; " . . . Stoliczka * considers also that these forms 

 are quite distinct. 



Horizon. Lower Chalk (England). Upper Greensand 

 (France). 



Localities. Sidmouth, Devonshire ; Folkstone, Kent ; 

 Escragnolles (Var), France. 



9. Nautilus libanoticus, sp. nov. 



1878. Ammonites Traskii, O. Fraas, Aus dem Orient, Theil ii. Geol. 

 Beobachtungen am Libanon, p. 97, Taf. iv. tig. 4 (not of Gabb). 



Sp. char. Shell much inflated, rapidly increasing, broadest 

 in the umbilical region. Umbilicus probably closed. Test 

 ornamented with prominent acute ribs, separated by inter- 

 spaces rather exceeding their own width. Some of the ribs 

 bifurcate in the region of the umbilicus. 



Remarks. All the specimens are casts more or less crushed 

 * Mem. Geol. Surv. India, Palaeont. Indica, ser. ii. 1866, p. 207. 



