MESODONTA. 221 



quite small in the type of Tomitherium, but the character may be one of 

 specific value only. 



The additional species referred to this genus in my report to Lieut. 

 G. M. Wheeler on the vertebrate fossils of New Mexico belong to the allied 

 form Pelycodiis. 



Tomitherium rostratum Cope. 



Paleontological Bulletin No. 3, p. 2, Aug. 7, 1872. Proceed. Amer. Philos. Soc., 1872, p. 470. Annual 

 Report U. S. Geol. Surv. Terrs., 1872 (1873), p. 548. 



Plato XXV, figs. 1-9. 



The portions of the skeleton of the type species preserved are : the 

 entire dentition of the lower jaw, minus the crowns of the outer incisor, 

 canine, and first premolar, the left ramus nearly complete, the extreme 

 angle being wanting ; the right humerus complete, with right ulna and 

 radius, the latter lacking the distal extremity ; a large part of the left ilium ; 

 the right femur nearly entire ; part of the left humerus, metatarsals, etc. 



This species was about the size of the Cehus capucinus. The first and 

 second premolar have but one root, the base of the second being about the 

 size of the base of the canine. The latter are cylindric at base. The 

 incisors form a parabolic outline, and have entire edges, the middle pair 

 transverse ones. Enamel generally smooth, premolars somewhat striate ; 

 an indistinct inner cingulum. 



The mandibular rami are quite stout, but not very deep ; the syra- 

 physeal portion long and oblique, and the coronoid and condylar portions 

 elevated, with axis at right angles to that of the horizontal portion. The 

 condyle is well elevated, and the coronoid process small ; the dental foramen 

 is half way between the margins of the ascending ramus, and opposite the 

 bases of the crowns of the molars. The inferior margin of the jaw shows 

 no tendency to inflection at a point immediately below this foramen, where 

 it is broken oft'. The mental foramen is divided, the exits being at points 

 opposite the fissures between the premolars 1-2 and 2-3. 



The humerus has a round head directed backwards and a little out- 

 wards. The tuberosities are rather small, of about equal size, and obtuse; 

 they inclose a short bicipital groove. The bicipital crests are very largely 

 developed, and extend to the middle of the shaft, inclosing an open groove 

 between them. The external is narrow and most elevated, the internal 



