SCOTT : LITOPTERNA OF THE SANTA CRUZ BEDS. 



153 





Measurements. 





Axis, width of anterior face . 



.062 



Astragalus, length 



■053 



Femur, proximal width . 



.091 



" width of trochlea. 



■037 



" distal width over condyles 



.0745 



" " distal end 



.030 



Tibia, proximal width . 



.070 



Metatarsal II, length . 



.122 



distal width. 



.050 



" " proximal width 



.021 



" thickness . 



•039 



" " " thickness 



.029 



Tarsus, length in median line 



.074 



" distal width . 



.0245 



" width 



.051 



Metatarsal III, distal width . 



.024 



Calcaneum, length 



.III 



Metatarsal IV, length . 



.116 



" width over sustentac 





" " proximal width 



.0215 



ulum .... 



.041 

 1 . 



" " distal width . 



-\ T J Till 



.025 



Localities. — Neither Ameghino, Mercerat, nor Lydekker gives any 

 localities for their specimens. No. 9230 was collected by Mr. Brown at 

 Halliday's Ranch on the Rio Gallegos and No. 15,798 by Mr. Hatcher at 

 Lake Pueyrredon. 



Theosodon patagonicus (Ameghino). 



Pseudoccelosoma patagonica Amegh.; Rev. Argent, de Hist. Nat., T. I, 

 1 89 1, p. 294. 



It has been pointed out in the foregoing pages that in several species of 

 Tlieosodou the two internal cusps of the upper molars are often connected 

 by a cingulum, but this is a very variable feature, differing even in the two 

 sides of the same jaw. Thus, in well worn teeth, the number of enamel- 

 lakes may be either two or three. In T. patagonicus the cingulum is 

 replaced by a pillar, in what appears to be a very constant fashion, and 

 equally constant is the presence of three lakes in the abraded grinding 

 surfaces. The species is not represented in the Princeton or New York 

 collections. 



Localities. — Not given. 



Theosodon karaikensis Ameghino. 



Theosodon karaikensis Amegh.; Nuev. Espec. de Mamif Cretac. y Terc, 

 1904, p. 54. 



Very inadequately known from two molars, an upper and a lower, which 

 leave the specific characters much in doubt. The distinctness of the 

 species is, however, made probable by the horizon in which it occurs. 



Locality. — Kar Aike. 



