G. C. Crick — On SopUtes from the Gault. 541 



Pecten Mater-Eymari, sp. nov. 

 Lower Eocene (Libyan Series) : opposite Esna. 

 Fig. 9. External view of one of the valves. 

 Fig. 10. Surface magnification of same, showing sculptm-e. 



Lower Eocene (Libyan Series) : Hills west of Jebel Zait. 

 Fig. 11. External aspect of specimen, with fairly perfect auricles. 



LiTHOPHAGUS CORDATUS, Lamarck. 

 Lower Eocene (Libyan Series) : Abu Zabel. 

 Fig. 12. View of adult form, exhibiting the right valve. 

 Fig. 13. Anterior aspect of same, showing the beaks. 

 Fig. 14. A young specimen. 



Arca Esnaensis, sp. nov. 

 Lower Eocene (Libyan Series) :" opposite Esna. 

 Fig. 15. External view of right valve, magnified twice. 

 Fig. 16. Magnified view of surface, showing sculpture. 



EXPLANATION OF PLATE XX. 



Ghama late-costata, Bellardi. 

 Lower Eocene (Libyan Series) : near Assiout. 

 Fig. 1. Outer view, showing the upper or more sculptured valve. 

 Fig. 2. Posterior aspect of same specimen. 

 Fig. 3. External view of the largest lower valve. 



Spondylus iEGTPTiAcus, sp. nov. 

 Lower Eocene (Libyan Series) : near Assiout. 

 Fig. 4. Front aspect of chief specimen. 

 Fig. 0. Back ,, ,, ,, 



Fig. 6, Profile ,, ,, ,, 



Macrosolen Hollowaysi, J. Sowerby. 



Middle Eocene (Mokattam Series) : between Guiset and Fayoum. 



Fig. 7. Outer view, exhibiting the left and part of the right valves \ „ „ ^^- 



-r, ' ' ° • 1 J. 1 \ same specimen. 



Fig. 8. ,, ,, , ,, right valve ) ^ 



(Except where otherwise mentioned, the figures on both plates are of the natural size.) 



III. — On a Deforbied Example of Hopliths tuberculatus, 

 J, Sowerby, sp., from the Gault of Folkestone. 



By G. C. Crick, F.G.S., 

 Of the British Museum (Natm-al History). 



THERE has recently been presented ^ to the British Museum 

 collection an Ammonite from the Gault of Folkestone that 

 seems to be worth}' of a short note. It is represented in the 

 accompanying figures. At first sight it appears to be a new species. 

 The shell is nearly complete and exceedingly well preserved ; 

 there has evidently been another half whorl to the specimen (see 

 Fig. a), but this, which apparently constituted the body-chamber, 

 has been broken away, leaving at the anterior end of the specimen 

 the surface of the last septum. The sculpture of the sides 

 instantly reminds one of the ornaments of the well-known SopUtes 

 tuberculatus, J. Sowerb}',- sp., but in that species the middle of 



1 By Mr. C. Coles. 



- J. Sowerby, Min. Conch., vol. iv (1821), p. 4, pi. cccx, figs. 1-3. The 

 originals of figs. 1 and 3 are in the British Museum collection. 



