EOSIEEN. 197 



Order SIEENIA. 



Family HALICOEID^. 



The occurrence of Sirenians in the Eocene beds of Egypt was first made kno^yn by 

 Owen, who described a natural cast of the brain-case of one of these animals under the 

 name JEotherium cegyptiacum *. This specimen was from the white Mokattam Lime- 

 stone of Cairo, and therefore from a rather lower horizon than the Qasr-el-Sagha beds. 

 A few years afterwards Filhol described f some teeth from the same limestone under 

 the name Manatiis coulombi, which may be synonymous with Eotherium cegyptiacum. 

 Lately much more information concerning Eotherium has been given by Dr. O. Abel, 

 who, in his important memoir entitled "Die Sirenen der mediterranen Tertiarbildungen 

 Osterreichs " J, gives an account of some recently collected remains of this animal. 

 This writer also proposes to publish shortly an exhaustive account of the remains of 

 Sirenians both from the neighbourhood of Cairo and from the Fayum, so that in the 

 present Catalogue it will only be necessary to give a short description of such remains 

 as are preserved in the British Museum and in Cairo. All the specimens from the 

 Fayum appear to belong to the genus Eosiren. 



Genus EOSIEEN, Andrews. 



[Geol. Mag. [4] vol. ix. (1902) p. 293.] 



Sirenia in which the three incisors and the canine are present at least in the upper 

 jaw. The first pair of incisors are enlarged downwardly-directed tusks ; the second 

 and third are small and probably lost early; their alveoli are situated somewhat on 

 the outer side of the rostrum close to the maxillo-premaxillary suture. 



Eotherium is distinguished from the present genus in several important particulars, 

 some of the chief of which are : — (1) the anterior incisors are not greatly enlarged and 

 tusk-like, and the two other incisors, though situated far back in the premaxiila, are 

 still large and placed on the edge of the jaw ; (2) the natural cranial cast on which 

 this genus is based differs so considerably from a cast of the brain-cavity in Eosiren 



* Owen, Quart. Journ. Geol. Soc. vol. xxxi. (1875) p. 100. The generic name Eotherium had been 

 previously employed by Leidy in 1853 for a genus of Perissodactyls, and therefore strictly the name 

 Eotheroides suggested by Palmer ('Science,' n. s. vol. x. 1899, p. 494) should be employed for this genus. 



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



t Abbandl. k.-k. geol. Eeichsanstalt, vol. xix. pt, 2 (Vienna,, 1904). 



