DERMAL BONES OF PARAMYLODON FROM THE 



ASPHALTUM DEPOSITS OF RANCHO LA BREA, 



NEAR LOS ANGELES, CALIFORNIA. 



By WILLIAM J. SINCLAIR. 

 (Read April 22, 19 10.) 



In the excavations conducted by the Department of Palaeontology 

 of the University of California in the Pleistocene asphaltum de- 

 posits at Rancho la Brea, near Los Angeles, large numbers of small 

 bones have been found, resembling closely the dermal ossicles de- 

 scribed by Dr. A. Smith Woodward (2, 3) from a piece of the 

 skin of a gravigrade edentate, Grypotherium listai, found in a cave 

 at Last Hope Inlet, Patagonia, and also resembling the previously 

 known dermal bones of Mylodon (i). 



In the asphaltum, two edentates have been found so far, one 

 apparently related to Mcgalonyx and the other referable to the 

 genus Paramylodon. As dermal bones, among the Gravigrada, are 

 known only in the Mylodontidae, there is every reason to regard 

 those presently to be described as pertaining to Paramylodon. Com- 

 parison of a skull and jaw from the asphalt with the figures of 

 P. nebrascensis Brown (4) from the Pleistocene locality of Hay 

 Springs, Nebraska, seems to indicate that they should be referred 

 to this species. 



In a preliminary paper on the Rancho la Brea deposits. Pro- 

 fessor Merriam (5) says, regarding the discovery of ossicles: 



During the first examination of the beds several small, pebble-like bones 

 were obtained which resembled the dermal ossicles of the ground-sloth, 

 Grypotherium, recently described by Dr. A. Smith Woodward from skin 

 fragments obtained in a cave at Last Hope Inlet, Patagonia. The ossicles 

 were in association with remains of a large ground sloth somewhat similar 

 to Mylodon in foot structure. Realizing that the peculiar conditions of accu- 

 mulation offered an especially favorable opportunity for preservation of the 

 dermal armor of a ground-sloth, during the second study of the deposits an 

 attempt was made to find a specimen in which the armor might be recognized. 

 Several hundred yards from the location of the first specimen, a large scapula 



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