Vol. 6] 



Merriam: Bear from Ranch o La Biro. 



1 65 



of TJrsus, but is larger and less concave posteriorly than in the 

 species at hand for comparison. The tooth may be referred 

 tentatively to Arctotherium, as it approaches this genus more 

 closely than to other forms. 



The foot-bones available for study consist of metacarpals 1, 

 3, 4 and 5, and the pisiform. They exceed considerably in size 

 the very largest known specimens of Arctotherium simum from 

 Potter Creek Cave, California; and are also much larger than 

 the largest specimens of the Recent Alaska bears available for 

 study. In all elements present the form is nearer to that of 

 Arctotherium than it is to that of Ursus, and the type seems 

 definitely referable to Arctotherium. This individual differs from 

 all of the specimens of Arctotherium simum available for study 

 in the greater width and general robustness of the metacarpal 

 elements. This is particularly true of metacarpal four, in which 

 the shaft is relatively very wide, and shows but little median 

 constriction. The rugosities on all of the elements are very 

 pronounced, indicating that this individual was probably in 

 advanced age. 



Even when the element of age is taken into consideration, it 

 seems improbable that this form could be classed in the same 

 specific group with Arctotherium simum, of which no specimens 

 in the collection from Potter Creek Cave are found to approach 

 the Rancho La Brea form in size and robustness. 



The tooth and foot specimens were obtained from two locali- 

 ties so far apart that there can be no possible suggestion that 

 they represent the same individual. As both specimens have the 

 characters of Arctotherium, and both represent an extraordinarily 

 large and robust form, it is desirable for the present to refer to 

 the Rancho La Brea type as a distinct species, which may be 

 known as Arctotherium calif ornicum. The elements of the foot, 

 no. 17754, are taken as the type of the species. 



Like the lion of Rancho La Brea, the bear described above 

 represents one of the largest and most powerful known car- 

 nivores of Pleistocene time. The measurements of the specimens 

 available are as follows : 



