XArTTLID,?:. 
31^9 
Nautilus Mokattaxnensis, Foord. 
1837. Xautilu.s imperialis, Fraa-=;, A us dem Orient, p. 119. (A’b^ of 
J. Sowerbv.) 
1875. Xautilus Forhesi, Owen, “On Fossil Evidences of a Sirenian 
Mammal from the Xummiilitic Eocene of the Mokattam Cliffs, 
near Cairo,” Quart. Journ. Geol. Soc. vol. xxxi. p. 103. {Xot of 
d’Archiac aiid Haime.) 
Sp. Char. Shell (cast) inflated, somewhat compressed on the 
sides, rather narrowly rounded on the periphery. Aperture very 
wide, semi-lunate. Umbilicus small, with steep sides. Septa 
approximate. Sutures flexuous, forming a conspicuous forwardly- 
directed lobe in the umbilical region, then curved backwards in a 
broad and shallow sinus, and again a little forwards, and making a 
narrow but distinct sinus on the periphery. The position of the 
siphuncle is not seen. Xone of the test is present. 
Remarlcs. This species resembles Xautilus imperialis., J. Sow., in 
the form of the sutures and the umbilicus, but the periphery is 
narrower and the aperture much broader than in Sowerby’s 
species. 
The assignment of this species to Xautilus Forbesi, d’Archiac and 
Haime, does not appear to be justified by the description and figures 
given of the latter h The description is not very complete, but the 
figures, if correct, represent a much narrower and more compressed 
shell than the one under consideration, the only point of resemblance 
between the two being the form of the sutures. It was thought 
better therefore to bestow a new name upon the Egyptian form, 
rather than to merge it in the Indian one, with which it does not 
seem to be clearly connected. 
Horizon. Eocene. 
Localities. Mokattam escarpment near Cairo. Egypt ? 
Kepresented in the Collection by two fragments, one of which 
(No. 3404) was presented by Sir E. Owen, K.C.B. ; the other (No. 
3403) was transferred from the Museum of Practical Geology. 
^ Descrip, cles Atiim, Foss, du Groupe Nummulitique de ITncle, livr. ii. 
p. 338, pi. xxxiv. ff. 12, 12 a. 
2 “ The Mokattam escarpment forms a long connected line of cliff, for the 
most part nearly inaccessible in front, but which can be easily ascended from 
some of the numerous lateral ravines .... The height is probably about 800 
feet above the Nile .... The beds are almost flat, having but a slight dip 
towards the desert. In a northerly direction the hill diminishes rapidly in 
height until it is covered by tlie red quartzose millstone-rock of Jebel 
Achmar. 
“ Apart from palajoutological considerations, the Nummulitic escai-pment. 
