DESCRIPTION OF A NEW FOSSIL SEA COW FROM 

 FLORIDA, METAXYTHERIUM FLORIDANUM. 



By Oliver P. Hat. 



Associate of the Carnegie Insiitution of V,\is}iii}{/i(nt. 



In the United States National Museum is a part of the upper right 

 maxilla of a sirenian which is of great interest. It was received along 

 with other specimens by Mr. George C. Matson, of the United States 

 Geological Survey, in 1911, and is recorded as having been found 

 1 mile west of Mulberry, Florida, in pit No. 7 of the Prairie 

 Pebble Phosphate Co. Matson figured this bone ^ under the name 

 " manatee." In the catalogue of the United States National Museum 

 the specimen has received the number 7221. The fragment presents 

 the hinder part of the right maxillary (pi. 1, figs. 1-3), extending 

 from its articulation with the palatine forward to the front of the 

 sockets for the anterior molar present. Near the front end, on the 

 outer side of the bone, is a break which represents the base of the 

 process which passed outward to join the malar bone. The maxilla is 

 solid and heavy and has suffered little erosion. The fragment contains 

 the hindermost molar tooth and the sockets, mostly filled by the roots, 

 of three other molars. An examination of the specimen shows that it 

 is closely related to the species which have been arranged under the 

 genus Metaxytherium. The fragment of the maxilla (pi. 1, figs. 1-3) 

 has a total length of 106 mm. The width at the middle of the penulti- 

 mate molar is 40 mm. ; the height at the same place, 39 mm. The whole 

 base of the malar process is present and it had a fore-and-aft extent 

 of about 44 mm. Its thickness was greatest behind and amounted to 

 about 18 mm. Toward the front the process thinned out to a sharp 

 edge. 



As already stated, there were originally present four molars (pi. 1, 

 fig. 3). The hindermost one is almost entire and is but little worn. 

 Of the two immediately in front of it there are present only the 

 roots; of the next one, only the sockets; and of the sockets of this 



> Bull. No. 604, U. S. Geol. Surv., pi. 12, figs. A, B. 



No. 2438-Proceedings U. S. National Museum, Vol. 61, Art. 17. 



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