Jurassic Mollusca from Arabia. 21 



extends to within a short distance of (he posterior end of the 

 guard ; the Arabian specimen agrees very well with the 

 median portion of such a form, but its ventral groove is 

 relatively narrower. Belemnites hastatus is widely distributed 

 and attains its maximum development in the zone of Pelto- 

 ceras biarmatum (Lower Oxfordian). In England the species 

 occurs throughout the Oxford Clay, and has also been recorded 

 from the Calcareous Grit *. Besides occurring in Europe, 

 fragments comparable with this species have been recorded 

 from Cutch f from the portions of the Charee group ranging 

 from the zone of Reineckia anceps through the zone of 

 Peltoceras athleta up into the zone of Aspidoceras perarmatum, 

 i. e. from the Lower Oxfordian up into the Corallian. The 

 species has also been recorded from the Jurassic rocks of 

 Hermon \. 



The specimen bears considerable resemblance to Belemnites 

 persicus, Weithofer §, from the Upper Jurassic (tenuilobatus- 

 beds) of North-west Persia, but the transverse section of that 

 species is more nearly circular. 



The hastate and depressed character of the fossil seems to 

 ally it also to Etallon's Belemnites astartinus ||. The extent 

 of the ventral groove, however, differs very much in the 

 figured examples which have been referred to this species. 

 Thus in Etallon's type specimen from the Astartian of the 

 Bernese Jura the groove extends over about two-thirds of 

 the length of the guard ; in an example figured by de Loriol 1] 

 from the beds of the zone of Ammonites tenuilobatus of Baden 

 (Argovia) it extends over about one-half the length of the 

 guard ; in an example figured by the same author ** from the 

 same horizon at Oberbuchsitten (Soleure) the groove is 

 almost entirely confined to the anterior third of the guard, 



» J. Phillips, op. cit. pt. 5, 1870, p. 112. 



t W. Waagen, Jurassic Fauna of Kutch (Pal. Indica), vol. i. The 

 Cephalopoda, Introduction. 



X Fritz Noetling, ' Der Jura am Hermon,' 1887, p. 33, pi. v. fig. 10. 



§ K. A. "Weithofer, Sitzungsber. d. k. Akad. d. Wissensch., Wien, 

 math.-naturw. CL, Bd. xcviii. Heft 8-10, 1890, p. 757, pi. i. fig. 4. 



|| A. Etallon, Lethaea Bruntrutana &c. pt. i. (Neue JJenkschriften der 

 allgemeinen Schweizerischen Gesellschaft fur die gesammten Natur- 

 wissenschaften, Bd. xviii.), 1861, p. 74, pi. i. fig. 1. 



51 P. de Loriol, Monographic paleontologique des couches de la zone a 

 Ammonites tenuilobatus (Badener Schichten) de Baden (Argovie), pt. i. 

 1876 (Mem. Soc. Pal. Suisse, vol. iii.), p. 12, pi. i. figa. 14 & 15. 



** P. de Loriol, Monographie paleontologique des couches de la zone a 

 Ammonites tenuilobatus (Badener Schichten) d'Oberbuchsitten et de 

 "Wangen (Soleure), pt. i. 1881 (Mem. Soc. Pal, Suisse, vol, viij, p. 7, 

 pi. i. fig. 5. 



