4 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. CI, 



besides some bones of land tortoises and a part of a metapodial of a 

 camel ; but these may belong to the Pleistocene. 



The sirenian tooth is of such a size and structure that it may 

 well have belonged to the species of animal that possessed the upper 

 jaw and teeth aboA^e named Metaxytherium floridanum. This tooth 

 is apparently a lower right third molar, and it is well worn (pi. 1, 

 fig. 5). The length is 25.5 mm. The width in front is 20 mm. 

 There are present two well-preserved roots. The anterior occupies 

 the width of the crown in front. On the outer side the cleft between 

 it and the hinder root is somewhat behind the middle of the length ; 

 on the inner side, considerably farther in front. The hinder root 

 is compressed from side to side. Unfortunately the enamel is 

 much broken away from the outer face of the tooth and somewhat 

 less from the inner face. At the front of the tooth there appears 

 to have been a deep valley, which extended backward between the 

 protoconid and the other elements of the front crest. This valley 

 has been worn quite to its bottom. Evidently it limited posteriorly 

 the strongly developed anterior cingulum. 



There appears to have been an accessory cusp at the base of the 

 metaconid, on its buccal side. The valley which separates the two 

 principal crests is seen to extend half way across the tooth from the 

 inner side. 



On account of the heavy wear there are not seen any remains of 

 accessory cusps where the transverse valley opened out on the outer 

 face of the tooth. For the same reason the exact structure of the 

 hinder talon can not be determined by the writer; but this talon is 

 well developed and there were two or three accessory conules. 



This tooth is provisionally^ referred to the species M etaxythermm 

 floridanum. 



EXPLANATION OF PLATE. 



Metaxytherium floridanum, new species. 



Figs. 1-3. Part of right side of upper jaw. X3/4. Type. 



1. View of lingual face. 



2. View of buccal face. 



3. View of alveolar face showing hindermost molar and the roots and 



socliets of three other teeth. 



4. Hindermost molar restored. XI. c^, anterior cingulum; c", c^, 



three conules belonging to hinder cingulum ; hy, hypocone ; mo, 

 metacone; tul, metaconule; pa, paracone; pi, protoconulus ; pr. pro- 

 tocone. 



5. Lower right hindermost molar of a referred specimen. XL 



