Dr. C. W. Andreics — Extinct Vertebrates from Egypt. 293 



further material is available. The occurrence of these three species 

 of Moeritheritim in a small area seems to point to the conclusion that 

 these animals were a dominant type of the fauna of the region, and 

 possibly it will be found that they form a group divisible into 

 several genera. 



EosiREN LiBYCA, gen. et sp. nov. (Figs. 1-3.) 



Two species of Sirenians have already been discovered in the 

 Eocene beds of Egypt, both being from the white Mokattam 

 Limestone of Cairo. Of these one was described by Owen under 

 the name Eotherhim cegyptiacum,^ on the evidence of a natural 

 cast of the cranial cavity ; the other was described by Filhol from 

 three lower molars, and was named Manatus Coulomhi,- Since both 

 these species, if indeed they are distinct, occur on nearly the same 

 horizon as the specimens from the Fayilm, it will be necessary to 

 consider whether the latter may not be identical with one or both 

 of them. 



According to Filhol the lower molars, which he made the types of 

 Manatus Coulomhi, differ only in small details from those of Manatus 

 australis, and he did not think that they could belong to Eothenum 

 cegyptiacum, because the brain of that species indicates a much more 

 primitive type of Sirenian than the living genus. In any case, 

 whether he was right in referring his species to Manatus or not, the 

 dentition of the Fayiim species is widely different from that of the 

 Manatees, and therefore it must be assumed to be distinct from 

 M. Coulomhi. 



In the case of Eotherium, cegyptiacum, as already mentioned, the 

 type is the cast of the brain-case, and fortunately it has been possible 

 to make a similar cast from one of our specimens, so that the two 

 forms are directly comparable. Dr. Elliot Smith ^ has examined 

 these casts, and he has come to the conclusion that the two forms 

 are distinct. 



It thus appears that our species is distinct from those previously 

 described from Egypt, and its relations must be sought elsewhere. 

 From the Eocene of Italy Zigno has described several Sirenians, the 

 best known being first named Salitherium veronense,^ but afterwards 

 referred by the same writer to a new genus, Prototherium,^ which, 

 however, he never fully defined, merely stating that it included 

 Eocene Sirenians in which the mandible bears a prominent posterior 

 (surangular) process. In many respects, e.g., in the general form 



1 Oweu : Quart. Joiuii. Geol. Soc, vol. xsxi (1875), p. 100. The generic name 

 Eotherium had been previously employed by Leidy iu 1853 for a genus of Perisso- 

 dactyla, and therefore, strictly, the name Eotheroides suggested by Palmer {Science, 

 N.S., vol. X, 1899, p. 494) should be employed for this Sirenian, but in the present 

 paper I prefer to continue to use the name by which it is best known. 



^ Bull. Soc. Philomathique de Paris, ser. vii, vol. ii (1878), pp. 124-5. 



^ Dr. Elliot Smith's descriptions of these and other bram-casts from the Fayum 

 will be published ia the proposed monograph on that district. 



* Zigno, " Sirenii fossili trovati nel Yeneto" : Mem. Inst. Veneto d. Sci., 

 vol. xA-iii (1875), p. 445. 



^ Zigno, " Quelques Observations sur les Sirenians fossiles " : Bull. Soc. geol. 

 France, vol. xv (1887), p. 731. 



