NOVEMBEB 2, 1906.] 



SCIENCE. 



567 



The type is the property of the Rev. Thomas 

 Condon, who loaned it to the Yale Museum. 

 It consists of the greater portion of a skull, 

 from which the matrix has not been fully re- 

 moved. The specimen was first described as 

 Oreodon by Leidy, but was afterward assigned 

 to the genus Merycochoerus by Bettany. After 

 the discovery of more complete remains of 

 Merycochoerus it was seen by Matthew and 

 Douglass that the specimens from the John 

 Day were very different, and the latter gave 

 them the name Promerycochoerus, making P. 

 superhus the type. The skull is large and 

 elongated. The upper contour is nearly 

 straight, the squamosal portions of the zygo- 

 matic arches are enlarged. The occiput is 

 not high, and the tympanic bullae are large 

 and elliptical. 



Merycoidodon, Eucroiaphus, Eporeodon, 

 Mesoreodon and Promerycochoerus appear to 

 be quite closely related, and, when more is 

 known of them, it may be found difficult to 

 generically differentiate some of them, yet it 

 is undoubtedly better to keep them separate at 

 present. Their near relationship seems to be 

 confirmed by the characters of the feet and 

 other portions of the skeleton. Merychyus, 

 Ticholeptus and Merycochoerus are apparently 

 more distantly related to the foregoing and to 

 each other. 



Merychyus Leidy. 

 TjTpe Merychyus elegans Leidy. Proceedings 



Academy Natural Sciences, Philadelphia, 



1858, p. 24. 



From the Miocene of the Niobrara Valley, 

 Nebraska. The type consists of portions of 

 maxillaries and a mandible with teeth, and 

 is preserved in the Academy of Natural Sci- 

 ences in Philadelphia. Size rather small, not 

 larger than Eporeodon. Premolar shorter 

 than the molar series, upper premolars in- 

 clined backward. From associated specimens 

 in the American Museum of Natural History 

 and the Carnegie Museum it appears that the 

 skull of Merychyus is low, and limbs and feet 

 long and slender. 



Ticholeptus Cope. 

 Type Ticholeptus zygomaticus Cope. Amer- 

 ican Naturalist, XII., 1878, p. 129. 



From the Ticholeptus (Deep Eiver) beds 

 of Smith River Valley, Montana. The type 

 specimen consists of the greater portion of a 

 skull with a mandible, preserved in the Amer- 

 ican Museum of Natural History. The skull 

 is considerably crushed and still partly im- 

 bedded in the matrix. It is short and high, 

 and the teeth moderately hypsodont. The pre- 

 molars are crowded, but not reduced in size. 

 There are small prelachrymal vacuities. Dr. 

 Matthews and myself have each discovered, in 

 Montana, skulls and parts of skeletons which 

 we have assigned to this genus, but they are 

 somewhat different, and one has longer limbs 

 and feet than the other. It is very certain, 

 as Dr. Matthews told me orally several years 

 ago, that Ticholeptus is a valid genus, for 

 the discovery of more complete specimens of 

 Merychyus shows that the latter is a quite 

 different animal. 



Merycochcerus Leidy. 

 Type Merycochoerus proprius Leidy. Pro- 

 ceedings Academy Natural Sciences, Phila- 

 delphia, 1858, p. 24. 



The material consists of portions of a max- 

 illary and a mandible with teeth from the 

 Miocene red-grit bed near Fort Laramie, Wy- 

 oming, and is now in the Academy of Natural 

 Sciences in Philadelphia. The skull, espe- 

 cially the posterior portion, is broad and low; 

 the basicranial axis forms a considerable 

 angle with the plane of the palate. The 

 nasals are shortened, and the animal undoubt- 

 edly possessed a long nose, or proboscis. The 

 teeth are hypsodont, the premolar is consider- 

 ably shorter than the molar series, and the 

 molars increase rapidly in length and height 

 posteriorly. From this genus must be ex- 

 cluded the so-called Merycochoerus laticeps 

 Douglass and M. altiramus Douglass from 

 Montana, which are still more specialized than 

 the type of Merycochoerus, the former of 

 which has been assigned by the writer to a 

 new genus which will shortly be published. 



Earl S. Douglass. 



Caenegie Museum, 

 October 15, 1906. 



