with Descriptions of New Forms. 



171 



larger in both transverse and anteroposterior diameters ; 

 P 4 is one fourth larger, P 3 the same size, P 2 abont one 

 fourth smaller, and P 1 alike in both. The total length of 

 dentition from XL 2 to I 3 inclusive is the same in both, 

 67 mm. 



1 0063 TYPE Y. P. M. 



Fig. 1. — Mesoeyon joseplii secundus, subsp. nov. Holotype. X -/3- 



Cat. Xo. 10063 is approximately the same length and 

 has the same bizygomatic diameter as 31. drummondanus 

 Douglass, bnt it differs from the latter in the following 

 respects: (1) larger I 3 ; (2) premolars crowded; (3) P 4 

 longer but not wider; (4) P 2 obliquely placed, and P 1 

 smaller and ovate in cross-section; (5) transverse part 

 of maxillo-palatine suture lies on a line back of the deu- 

 terocone of P 4 , while in 31. drummondanus it is on this 

 line; (6) bullae more ovate and their long diameter less 

 oblique to the sagittal plane in 31. drummondanus; (7) 

 smaller brain-case diameter. 



/0063 TYPE 

 Y. P. M. 



Fig. 2. — Mesoeyon joseplii secundus, subsp. nov. Holotype. X 2/3. 



31. joseplii secundus, 31. joseplii, and 31. drummondanus 

 are closely allied and yet show clearly recognizable differ- 

 ences. Xo. 10063 and 31. joseplii joseplii are middle John 

 Day and from the John Day Basin, while the type of the 

 other species was collected a little east of Drummond, 



