R. Bullen Newton — An Echinoid from Sinai. 443 



cornutus also from Mont Garcbe, wLicli are true Cenomanian species ; 

 and, moreover, we have it on the authority of Professor Rothpletz ^ 

 that no Turoniau rocks have been identified in the Sinai Peninsula, 

 thus fully confirming the previous virork of Duncan, who from an 

 examination of the assemblage of fossils in this region was led to 

 regard it as generally of a Cenomanian character. This horizon 

 is also supported by the specimens collected by the Geological 

 Survey of Egypt, which contain such fossils in association with 

 Linthia oblonga as Exogyra Africann and JExogyra Olisiponensts. 



In connection with Hemiaster cnhicus it is interesting to note that 

 according to modern writers that species is a frequent Cenomanian 

 fossil of Sinai ; yet Duncan never identified it in the Bauerman 

 Collection, nor has the present writer been able to I'ecognize it among 

 the specimens collected by Mr. Barron. Professor A. Rothpletz - 

 noted the occurrence of S. cnhicus in the Cenomanian beds of 

 Sinai during 1893 ; M. Fourtau ^ recognized it at Wadi Budra, etc., 

 in beds of Lower Cenomanian age ; Dr. Blanckenhorn * has also 

 listed the species from similar regions of Sinai ; whilst Dr. Hume * 

 has met with it at Jebel Gunnah, in the eastern part of the peninsula, 

 associated with Fseiidodiadema variolare and Seterodiadema Ubycum. 

 M. Fourtau's latest contribution on this subject calls attention to 

 the eccentricit}'^ of the apex in H. cubicus, and the varieties of form 

 that he has observed in the species, his examples coming from the 

 neighbourhood of the Convent of St. Paul in the Arabian Desert, 

 where the species is said to be characteristic of the base of the 

 Cenomanian of Egypt. But it is not likely that any confusion 

 could have occurred in the identification of these echinoids when 

 the details of the test are considered. There is the great 

 difference in form, as also in the pore structure of the anterior 

 ambulacrum, whilst the presence in Linthia oblonga of a lateral as well 

 as the peripetalous fasciole creates even a more striking separation. 

 This lateral fasciole, which in the posterior region is situated beneath 

 the anal orifice, is, unfortunately, not always definable, so much 

 depending upon the state of preservation of the test; but it is 

 traceable on Duncan's specimens in the Geological Society and also 

 on some of those collected by Mr. Barron. There is a stratigraphical 

 distinction also which deserves to be mentioned. According to 

 M. Fourtau, If. cubicus belongs to the base of the Egyptian Ceno- 

 manian, whereas L. oblonga, from its association with Exogyra 



1 Eothpletz, A., " Stratigrapliisclies vou der Smailialbinsel' ' : jS'eues Jahrbuch, 

 vol. i (1893), pp. 102-104. 



- Eothpletz, A., " Stratigraphisches von der Sinaihalbinsel " : jSTeues Jahrbuch, 

 vol. i (1893), pp. 102-104. 



3 Fourtau, R., "La Cote Quest du Siuai," Bull. Soc. Khediviale Geographie 

 (Le Caire), 1898, ser. v, No. 1, pp. 1-35; "Revision des E'ehinides Fossiles de 

 l'E'gj7)te," Mem. Instit. E'gyptien, vol. iii (1899), fasc. 8, pp. 605-608, 628 ; " Note 

 sur Remiaster eubieus, Desor, et ses variations," Bull. Mus. Hist. Nat. [Paris], 

 1903, No. 3, pp. 177-180. 



* Blanckenhorn, Max, " Neues zur Geologic und Palaontologie Aegyptens " : 

 Zeitsch. Deutsch. Geol. Ges., vol. Iii (1900), see chart facing p. 33. 



5 Hume, W. F., " Geology of Eastern Sinai": Geol. Mag., 1901, p. 203. 



