Mylodon harlani, from Rock Creek, Texas. 



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Mylodon garmani Allen. 



This, the latest species of Mylodon to be differentiated, was 

 described by Allen* in 1913, as follows : 



" Type. — Well preserved skull and. parts of the skeleton, 

 No. 8429 M.C.Z., from the Pleistocene of the Niobrara River, 

 Nebraska. Samuel Garman, 1880. 



" Horizon. — The locality is practically the same as that of 

 the Hay Springs fauna, probably Mid Pleistocene, though 

 precise details of the situation are lacking. 



" General characters. — A large species about the size of 

 M. harlani, from which it differs conspicuously in the con- 

 formation of the last molars, the fifth upper molar being in 

 outline like a figure 8 with a constriction in the middle on 

 either side ; the fourth lower molar much elongated and later- 

 ally compressed, with the greater axes of the internal lobes 

 nearly longitudinal instead of transverse. Skull high and 

 much narrowed from side to side, with high sagittal crest ; 

 pterygoids deep and rounded in side view, palate long and nar- 

 row with a very deep and narrow interpterygoid fossa. Eden- 

 tulous portion of the tip of the rami much contracted." 



The remainder of the description is too full to be quoted in 

 extenso. 



Paramylodon Brown. 



Brown f gives the following description of this genus : 



" This genus is founded on a nearly perfect skull and lower 

 jaw in the American Museum collections (No. 2780), with 

 associated skeletal material including five cervical vertebrae, 

 tibia, fibula, calcaneum, astragalus, lunar, middle digit of 

 manus, and ribs, found by the Expedition of 1897 near Hay 

 Spring, Nebraska. . . . 



" The following characters distinguish it from allied genera : 



4 



" Skull elongate ; muzzle inflated ; dentition — ; first upper 



molar the largest of the series ; last lower molar trilobate ; 

 first lower molar without opposing tooth. 



" Paramylodon seems to have been less specialized than 

 Mylodon, retaining features of the older, more primitive 

 sloths. From the long nasals it seems improbable that it had a 

 proboscis, while the greatly inflated muzzle, and the large 

 movable premaxillge, indicate a large prehensile lip. The 

 reduction of the twelfth nerve shows a less specialized tongue 



* Allen, G. M., Mem. Mus. Coinp. Zool., vol. xl, No. 7, pp. 319-346, pis. 1-4, 

 1913. 



f Brown, B., Bull. Amer. Mus. Nat. Hist., vol. xix, pp. 569-583, pis. 50, 51. 

 1903. 



