NEWTON: luWKR TKRTIARY MOLLUSCA OF Till': J'AYUM. 67 



Among- the Pelecypoda, Ostreiforni sliells are largely represented, 

 belonging to the genera Grxjphcea, Ostrea, and Alectryonia, the last 

 genus having })oth its valves plicated; Alectri/onia Clot-heyi is fretinently 

 met with in the Fayiim, occurring in the Kaviue Series up to nearly 

 the top of the Qasr el Sagha Series. The species is also represented 

 in the ]\[okattam rocks near Cairo, and in the Lutetian deposits of 

 Tunis, where it is associated with Carolia iilacunoides. 



The Auoraiidfe are represented by Carolia placunoides, a form, 

 related to the recent Placuna of the Pacific and the genus Anoinia. 

 In the young state this shell exhibits a large byssal foramen in the 

 cardinal region which is gradually closed up with age, and forms 

 interiorly a prominent transversely oval cartilage process. The species 

 is found throughout the Fayum Lower Tertiary deposits, but more 

 particularly in the Qasr el Sagha Series. It also occurs in other areas 

 of Egypt, and in Tunisia, where it is recognized as of Lutetian age. 



Pectens are rare, only one form having been found belonging to 

 Pseudamusium ; the genus Plicattda is well represented, one species, 

 P. pohjmorpha, being characteristic of the Qasr el Sagha Beds ; there 

 are three species of Spondylus which occur in the Lower Mokattam 

 beds, that of S. ^yyptiacus being probably the most frequently 

 found ; the interesting genus Vulsella is restricted to the Lower 

 Mokattam Series, although one of the species, V. crispata, ranges from 

 that horizon to the Priahonian of the Siwah Oasis of Egypt ; species 

 of the jS^uculidje are apparently rar^s, only one being referred to, while 

 some forms of Area and a species of Cucullcea, etc., are regarded as of 

 Upper Mokattam age; Glycymeris {= Pectunculus), several species 

 of Cardita, and Crassatellites also occur ; species of Lucina are fairly 

 common, as well as the allied genus, Diplodonta, Divaricella being also 

 present; among the Cardiidse, Zf^'.i'ocrtr^mwi is represented; the presence 

 of Corlicula in the Upper Mokattam Beds (Qasr el Sagha) is of interest 

 in proving the estuarine character of those deposits ; under the family 

 Veneridfe are included several species of Meretrix, M. sulcataria of 

 Lamarck being of importance as occurring besides in the Eocene deposits 

 of the Paris Basin ; Telliniform shells include the genera Macaliopsis 

 and Arcopayia, while the genus JIacrosole)i of the Solenidse occurs 

 throughout the Mokattam Beds of Egypt, and is also found in the 

 well-known Bracklesham deposits of England; a fine form of 

 Plioladomya occurs in the rocks of the island on Birket el Qurun, as 

 well as Mactra compressa, a species characteristic of the Bartonian of 

 Prance and England; two species of Corhula are noted from the Upper 

 Mokattam Beds, which is again evidence in favour of the estuarine 

 origin of the deposits. 



The Scaphopoda group is represented by one form, Fustiaria Stromeri. 



The Gastropoda contain genera of the families Fissurellidfe, 

 Patellidoe, Trochidte, and Neritidfe, the last represented by the 

 familiar Velates Schmidelianus, Avhich is restricted to the Lower 

 Mokattam deposits of Egypt, being known also to range from the 

 lowest to the Middle Eocene horizons in India and Europe; 2\trrifell(B 

 are numerously represented in the Fayum throughout the Mokattam 

 Series; the Capulidte contain Cahjptrcea aperta, a species well known 



