1856.] 311 



Lamprosoma occipitale, nob. 

 Syn. Rhinostoma occipitale, Proceed. A. N. S. vol. vii. 1854, p. 95. 



Char. 15 rows of smooth quadrangular scales ; color milk white above, with 

 34 transverse black bands, including one upon posterior part of head ; six com- 

 plete rings of black upon the tail, and one incomplete just behind the anus ; 

 jaws, chin, throat and abdomen white ; interspaces between rings upon under 

 part of tail white. Length of head, neck and body 10 inches 1 line ; of tail 1 

 inch 7 lines. Ab. scut. 158 ; sub. caud. 34. 



Habitat. Mohave Desert, Southern California. One specimen in Smithsonian 

 Institution, collected by Dr. A. L. Heermann. 



Gen. Remarks. Allied to Simotes, but in the latter the nostril opens between 

 two plates, and the snout is conical. 



Notices of extinct Vertebrata discovered by Dr. F. V. Hayden, during the expedition to 

 the Sioux country under the command of Lieut. G. K. Warren. 



By Joseph Leidy, M. D. 



MAMMALIA. 



1. Merychippus insignis, Leidy. 



Founded upon a first and second molar of the upper jaw of a remark- 

 .able equine animal, in the structure of the teeth approximating the ruminant 

 family. 



The teeth are inserted by distinct fangs ; and the crowns strikingly resemble 

 the true molars of ruminants. There are four demiconoidal lobes holding the 

 same relationship with one another as in the latter, especially as in the Deer. 

 The outer lobes have almost the exact form as in the true molars of Oreodon. 

 The inner lobes resemble those of ruminants, but are complicated with acces- 

 sory folds as in the horse. No cementum fills up the interspaces of the lobes 

 nor does it appear to have existed as part of the structure of these teeth. 



Antero-posterior diameter of first molar 12 lines ; transverse 8 lines. 

 " " " second molar 10 " " 9 " 



From the tertiary beds of Bijoux Hills on the Upper Missouri. 



2. HiPPARioN (Hippodon) speciosum, Leidy. Pr. A. N. S. VII. 90. 

 Accompanying an inferior molar, there is an unworn upper molar and por- 

 tions of three otlier upper molars, worn away in various degrees, which appear 

 to be the teeth of Ilij^parion, and appear to belong to the same animal as the 

 tooth referred to Hippodon. The inferior molar slightly worn is l\ inches long. 

 10 lines wide, and 4 lines thick. The unworn upper molar is 20 lines long, 11 

 lines antero-posteriorly, and 9 lines transversely. 



Found with the preceding at Bijoux Hills. 



3. Leptarctus primus, Leidy. 



Founded on a single specimen of an upper molar tooth, which bears consider- 

 able resemblance to the fourth superior molar of the Coati. The tooth has a 

 trihedral crown as in the latter and also has three fangs. The inner pair of 

 tubercles of the crown are nearly equal in size; that anteriorly being less well, 

 and that posteriorly better developed than in the Coati. Of the three outer 

 tubercles that anteriorly is more like a talon than a cusp, and the posterior 

 tubercle is better developed in its relation with the median one. I think the 

 specimen represents a genus allied to the Nasua. 



Found with the preceding at Bijoux Hills. 



4. Thespesius occidentalis, Leidy. 



Among the collection of vertebrate remains are two apparent caudal verte- 

 brae and a first phalanx of some huge animal, which I suspect to be a Dinosau- 

 rian, though they maj^ have belonged to a mammalian. The phalanx and one 



