SCOTT : LITOPTERNA OF THE SANTA CRUZ BEDS. 



73 



No. 



No. 



No. 



9267. 



20. 



15,996. 



.0915 





.089 



.0075 





.008 



.004 





.003 



.074 





.074 



■038 





.038 



.006 





.005 



.003 





.003 



.010 





.010 



.006 



.005 



.005 



.Oil 



.0115 



.012 



.007 



.0075 



.008 



.011 



.on 



.0115 



.0085 



.0095 



.010 



•036 



.036 



.036 



.011 



.oil 



.0115 



.0095 



.009 



.009 



.012 



.012 



.013 



.0095 



.009 



.009 



.013 



.014 



.013 



.0085 



.008 



.008 



.019 





.017 



Lower dentition, length ij—m^ 

 13-, antero-posterior diameter 



" transverse diameter 

 Lower premolar-molar series, length 



" premolar series, length 

 P^, length 



" width 

 Pj, length 



" width 

 Pj, length 



" width 

 Pj, length 



" width 



Lower molar series, length 

 My, length 



" width 

 Mj, length . 



" width 

 Mg-, length 



" width 

 Mandible, depth below pg^ 



Localities. — Not given for type; No. 15,996 was collected by Mr. 

 Peterson, four miles south of Coy Inlet, and No. 9267 by Mr. Brown, but 

 the locality record has unfortunately been lost. 



Proterotherium perpolitum Ameghino. 



(Plate IX, Fig. 9.) 



Proterotherium perpolitum Amegh.; Enum. Synopt., etc., 1894, p. 36. 



This species, which is very inadequately known from a single tooth 

 (m- of the right side), may be distinct, or may be merely a variant of the 

 preceding one. The type agrees closely in size with the corresponding 

 tooth of P. intermedium and also in the very unusual character of having 

 the two external cusps of almost equal width, but, on the other hand, the 

 hypocone, which in P. intermedittm is relatively very large, is entirely 

 wanting in the present species, and thus the tooth has a somewhat triangu- 

 lar outline. 



The type-specimen measures 11 mm. in antero-posterior, by 17 mm. in 

 transverse diameter. 



Locality. — Not given. 



