MATTHEW, NEW SIRENIAN FROM PORTO RICO 39 



pretation of the alveoli iii the jaw in this and other genera is apparently 

 somewhat doubtful. Pending the publication of Abel's final conclusions, 

 it seems best to accept his present views provisionally, as I have done in 

 the above diagnosis and discussion of affinities of H. antiUense. The 

 number of true molars is considered as unchanged from the primitive 

 series of three, and the alveoli of the tooth preceding them are considered 

 as of milk-molar four, although there is no proof that this tooth had a 

 successor in Halitlierium. 



Bibliography 



Abel, O. : Die Sirenen der mediterranen Tertiarbildungen Oesterreichs. Abh. 



k. k. Geol. Reichsanst. Bd. XIX, Heft 2, ss. i-vi, 1-223, taf. i-vii. 1904. 

 Abel, O. : Die Milchmolaren der Sirenen. Neues Jahrb. Jahrg. 1906, Bd. II, 



ss. 50-60. 1906. 

 Abel, O. : Die eocanen Sirenen der Mittelmeerregion. Palseontographica, Bd. 



LIX, s. 288-360, taf. xxx-xxxiv. 1912. 

 Andrews, C. "^^^ : A Descriptive Catiilogue of the Tertiary Vertebrata of the 



Fayum, Egypt., pp. 1-324, pll. i-xxvi. Published by the British Museum, 



London, England. 1906. 

 FiTziNGEK, L. J. : Bericht uber die in den Sandlagern von Linz aufgefunden 



fossilen Reste eines urwelthichen Sangers. Ber. Mus. Franc-Car. in Linz, 



pp. 61-72 mit 1 taf. 1842. 

 Lepsius, G. R. : Halitherium schinzi, die fossile Sirene des Mainzer Beckens. 



Abh. Mittelrhein. geol. Vereins. Bd. I, s. 1-200, taf. i-x. 1882. 

 Lydekker, R. : On a remarkable Sirenian Jaw from the Oligocene of Italy and 



its bearing on the Evolution of the Sirenia. Proc. Zool. Soe. London, 1892, 



pp. 77-83. 1892. 

 Thomas. Oldfield, and TjYdekker, R. : On the Number of Grinding Teeth pos- 

 sessed by the Manatee. Proc. Zool. Soc. London, 1897, pp. 595-600, pi. 



xxxvi. 1897, 



