14 Messrs. I vton and G. C. Crick on some 



suggest a corapai i Retowski's genus Tithonoceras* ^ 



which was fouudt a new species T. zitteli'\ from the 



Tithonian of the , 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 

 genua, 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 Tithono- 

 ceras it is rather concave. 



The Arabian species appears to be intermediate between 

 such a form as Nautilus hexagonus and the genus TithonoX 

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

 ennianus from the Kimeridgian rocks of Atschabo in 

 Soraaliland. 



Loc. Valleys between the villages of Al-Kura and Sammay 

 about 15 miles N.E. of Dihala. i 



B. A M M N r D E A. 



Genus Perisphinctes, Waagen. 



With one possible exception, the Ammonites in the collec- 

 tion are referable to the genus Perisphinctes. All are more 

 or less imperfectly preserved, but, though very much cruslied/ 

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

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

 snecimens, therefore, renders the identification of the species 

 particularly difficult. 



Penspliinctes cl. torquatus (J. de C Sowerby). 

 (PI. III. figs. 1 a, b.) 



1840 Ammonites torqwitus, J. de C. Sowerby, Trans. Geol. Soc. [2] 



vol. V. pt. 2, p. 719, pi. Ixi. tiu;. 12 & expl. ; , 



1863. ? Ammonites torquatus, i . de C. Sowerby ; H. F. Blanford, Jourii. 



Asiatic Soc. Bengal, vol. xxxii. no. 2, p. 130, pi. iii. tigs. 6, (5 «, 7, 



7 a, 8. 

 ? 18G5. Ammonites torquatus, J. de C. Sowerby ; II. F. Blanford, in 



J. W. Salter and II. F. Blanford, Pateont. >iiti, p. 80. 

 1875. Perisphinctes torquatus (J. de C. Sowerby); W. Waagen, .In-. 



rassic Fauna of Kutch (Pal. Indica), vol. i. Cephalopoda, pt. 4, p. 1 ; H, 



pi. liv. 

 1898. Perisphinctes torquatus (J. de C, Sowerby): .J. v. Siemiradzki, 



Palseontograpbica, Bd. xlv. p. 263. 



The best-preserved Ammonite in the collection was 

 partially exposed on the surface of a small slab of limestnne.- 



* O. Retowski, " Die tithoniseben Ablagerungen von Tlieodosia,'' 

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

 t O. Retowski. op. fit. p. 223, p . xiii. iju;.^. i> a, b. c. 



