CONDYLAETHRA. 405 



Measurements. 



M. 

 Length from Pm. ii to M. ii inclusive- 052 



Diameters of M.ii 5 '*°t''''''P°«*'="°'' ^^ 



■< transverse 010 



Depth of ramus at M. ii 022 



Width of ramus at M. ii 016 



Depth of ramus at Pm. ii 019 



From the Puerco formation of New Mexico; D. Baldwin, discoverer. 

 HEMITHL^US Cope. 



American Naturalist, 188-2, p. 832. (Sept. 28.) 



? 1 4 3 



Known from dentition only. Dental formula: I.^; C. -; P-m.-; M.- 



•^ V 1 4 3. 



Superior true molars with two external cusps and an internal V. No inter- 

 mediate tubercles, nor internal tubercles or cusps, other than the apex of 

 the V. Third and fourth premolars with one external and one internal cusp. 

 Inferior true molars with two anterior and two posterior cusps, with some 

 supplementary tubercles. First inferior premolar one-rooted ; second with 

 two roots and a simple crown. Crowns of second and third unknown. 



This genus has the premolar teeth of the species of Anisonchus with 

 the inner lobe conical. Its principal peculiai'ity consists in the absence of 

 the posterior internal cusp, which is such a prominent feature in Anisonchus 

 and Haploconus. 



Two species are known, both from the Puerco formation. 



HEMITHLiEUS KOWALEVSKIANUS Cope. 



American Naturalist, 1882, p. 832. (September 28.) 

 Plate XXV /; figs. 6-7. 



This animal is represented in my collection by parts of the crania of 

 two individuals. One of these includes a right maxillary bone with bases 

 of six molars, and crowns of four, the last being absent; and a left mandi- 

 bular ramus with bases of six molars, and crowns of four, the Nos. i, ii, v, 

 and vi. The second specimen includes a right maxillary with the posterior 

 four molars preserved, and the right ramus with the true molars i and ii 

 preserved. 



In size this species yields to the Anisonchus coniferus and the Haplo- 

 conus entoconus, but is larger than the A. sectorius. The third and fourth 



