14 Messrs. K. B. Newton and G. 0. Crick on some 



suggest a comparison with Retowski's genus Tithonoceras* , 

 which was founded upon a new species T. zitteli\ from the 

 Tithonian of the Crimea, but the depression of the outer 

 portion of the lateral area and the longitudinal sulcus on the 

 periphery near its margin are not nearly so distinct as in that 

 genus, and there is an absence of any depression along the 

 median lineof the periphery — in fact, in the Arabian specimens 

 the periphery is feebly convex, whilst in the genus Titliono- 

 ceras it is rather concave. 



The Arabian species appears to be intermediate between 

 such a form as Nautilus hexigonus and the genus Tithono- 

 ceras, and probably finds a near ally in Dacque's Nautilus 

 ennianus from the Kimeridgian rocks of Atschabo in 

 Somaliland. 



Loc. Valleys between the villages of Al-Kura and Samma, 

 about 15 miles N.E. of Dihala. 



B. Ammonoidea. 



Genus Perisphinxtes, Waagen. 



With one possible exception, the Ammonites in the collec- 

 tion are referable to the genus Perispliinctes. All are more 

 or less imperfectly preserved, but, though very much crushed, 

 portions of the test are usually present. In no case, however, 

 is it possible to see the suture-line. The condition of the 

 specimens, therefore, renders the identification of the species 

 particularly difficult. 



Perispliinctes c£. torquatus (J. de C. Sowerby). 

 (PI. III. figs, la, b.) 



1840. Ammonites torquatus, J. de C. Sowerby, Trans. Geo!. Soc. [2] 



vol. v. pt. 2, p. 719, pi. lxi. tig. 12 & expl. 

 1863. 'i Ammonites torquatus, J. de C. Sowerby ; H. F. Blanford, Journ. 



Asiatic Soc. Bengal, vol. xxxii. no. 2, p. 130, pi. iii. tigs. 6, 6 a, 7, 



7 a, 8. 

 ? 1805. Ammonites torquatus, J. de C. Sowerby ; H. F. Blanford, in 



J. W. Salter and H. F. Blanford, Palseont. Niti, p. 80. 

 1875. Perispliinctes torquatus (J. de C. Sowerby); W. Waagen, Ju- 

 rassic Fauna of Kutch (Pal. Iudica), vol. i. Cephalopoda, pt. 4, p. 191, 



pi. liv. 

 1898. Perispliinctes torquatus (J. de C. Sowerby); J. v. Sierniradzki, 



Palaeontographica, Bd. xlv. p. 263. 



The best-preserved Ammonite in the collection was 

 partially exposed on the surface of a small slab of limestone. 



* 0. Retowski, " Die titboniseben Ablageiungen von Theodosia," 

 Bull. Soc. Imp. Nat. Moscou, 1893, no. 2 & 3, p. 222. 

 | O. Retowski. op. cit. p. 223, p . xiii. tigs. 2 a. 6. c. 



