220 M. R. Thorpe — John Bay Pr ornery cochoeri, 



they were collecting at definite periods, this doubt seems 

 very nearly to vanish. The geographic distribution of 

 the various species may be tabulated as follows : 



N. Fork 

 Bridge Turtle Haystack Clarno John Day 

 Creek Cove Valley Bottom Kivert 



P. superhiis 20 + 7* 3 + 2 ? 1 



P. leidyi 2 + 1 1 + 1 1 1 



P. macrostegus 3 1 + 2 1 + 3 



P. inflatus, n. sp 1 



P. chelydra + 1 1 + 1 



P. lulli, n. sp 1 



P. microcephalus, n. sp.. . + 1 



P. marshi, n. sp 1 



P. latidens, n. sp 1 



Desmatochoerus curvidens, 



subgen. et sp. nov 1 



* The second figure refers to specimens of doubtful locality, 

 t Fifteen miles above junction with main stream. 



Up to the present, it has been considered that Promery- 

 cochoorus was limited to the upper John Day, but if it is 

 assumed that the green matrix is confined to the middle, 

 and the gray and buff to the upper horizon, then, using 

 70 specimens in this collection as a basis, it is found that 

 approximately 14 per cent were collected in green strata 

 and hence belong to the middle John Day. The remain- 

 der, 86 per cent, were enclosed in gray or buff matrix, 

 with the exception of two specimens showing brown coun- 

 try rock. The species having representatives formerly 

 enclosed in matrix bearing an undoubted green color are 

 as follows: P. leidyi, 1; P. macrostegus, 3; P. superhus, 

 3; P. lulli, 1; P. microcephalus, 1; and Desmatochoerus 

 curvidens, 1. 



In regard to individual age, again using these 70 speci- 

 mens as a basis, 11.5 per cent have milk dentition, 73 per 

 cent are fully adult and about middle-aged, while 11 per 

 cent are post-mature and the remainder very old. 



Descriptiox of Species. 



Promerycochoerus superhus (Leidy). 



Synonyms : Oreodon superhus Leidy, Proc. Acad. Nat. Sci, 

 Phila., 22, 111-112, 1870 ; Eporeodon superhus Marsh, this Jour. 

 (3), 9, 250, 1875; Eucrotaphus superhus Cope, Bull. U. S. Geoh 



