298 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 41. 



teeth in the present form, as will be shown later, is not Hke that of 

 the Crocodile and Alligator, and, when considered with the great 

 disparity in the proportional extent of the dental series, appears to 

 justify their generic separation. On that account the new generic 

 name Bracliychampsa is proposed for its reception. Under this 

 genus I would include the species Bottosaurus perrugosus Cope from 

 the Arapahoe beds of eastern Colorado, which Cope provisionally 

 assigned ^ to the New Jersey genus Bottosaurus. 



The type of this species cannot now be located, but in the original 

 description is said to consist of a "fragmentary dentary, vertebrae, 

 and pieces of the skull." Cope says: "There is a slight difference 

 in the sizes of the alveoli, but not such as is usual in Tertiary croco- 

 diles." In view of the character of the dentition shown by this 

 newly discovered specimen, "the slight differences, etc.," noted 

 above appear especially significant when taken into consideration 

 with the similarity of their geological occurrence. 



The classification of this form may be best expressed by the 

 following : 



Order. — Crocodilia. 



Suhorder. — Eusuchia. 



Family.- — Alligatoridse. 



Genus . — Brachycliampsa. 



Species. — Brachycliampsa montana. 



The genus Brachycliampsa will now include the two species B. mon- 

 tana, B. {Bottosaurus) perrugosa (Cope) . 



BRACHYCHAMPSA, new genus. 



The characters of this genus are included in the description that 

 follows of Brachycliampsa montana, the type-species. 



BRACHYCHAMPSA MONTANA, new species. 



Plates 26 and 27. 



Type. — The anterior two-thirds of the skull, accompanied by 

 detached fragments of the posterior portion. Cat. No. 5032, Amer. 

 Mus. Nat. Hist. Collected by Barnum Brown. 



Type-locality . — Twenty-five miles southeast of Lismas, Dawson 

 County, Mont. 



Horizon. — Upper sandstone, "Hell Creek Beds," Lance forma- 

 tion, Upper Cretaceous. 



Description. — The type-specimen is a short, broad-snouted skull, 

 the length from the level of the front border of the orbits being only 

 7 mm. greater than the width at the same point. Excepting a few 

 detached fragments, the posterior portion of the skull behind the 

 orbits is missing (PL 26). The remaining part is fairly complete 



' Bull. Geol. and Geog. Survey of Terr., vol. 1, 1874-5, p. 27. 



