106 EDENTATA. 



the lower series of cheek-teeth 0,125, and that of the portion of the 

 mandible in advance of the first tooth 0,152. The first tooth in each 

 jaw is extremely minute and wears horizontally ; it may be some- 

 times absent ; the palate is narrower than in any other species. 

 This species connects the members of the following group with 

 Scelidotherium. 



Hab. South America (Patagonia and Argentine Republic). 



M. 3591 a. Cast of the right ramus of the mandible, showing a 

 section of the four teeth. The original, together with the 

 opposite ramus, was obtained by Darwin from the Pleisto- 

 cene of Punta Alta, Bahia Blanca, Patagonia, and is pre- 

 served in the Museum of the Royal College of Surgeons 

 (No. 3490). It is the type of the species, and is figured by 

 Owen in the ' Zoology of the Voyage of the Beagle,' pt. 1, 

 p. 69, pis. xvii. fig. 5, xviii., and xix. 

 Presented by the Council of the Royal College of Surgeons. 



GROUP B. 



The premaxillae short and separated from the nasals ; the ante- 

 rior portion of the mandible equally short, its length being much less 

 than that of the dental series. 



Mylodon harlani, Owen 1 . 



Syn. Orycterotherium missouriense, Harlan 2 . 

 Xkibradys antiquus, Leidy 3 . 



This is the type species. The first and second teeth in the lower 

 jaw are approximated, and the plane of wear of the former was 

 probably horizontal. 



Hob. North America (Kentucky, Missouri, Mississippi, South 

 Carolina, and Georgia). 



7375. Cast of a portion of the right ramus of the mandible, showing 

 the alveolus of the first tooth and the three posterior teeth. 

 The original, which is the type, was obtained from ' Big- 

 Bone-Lick,' Kentucky, and is preserved in the Museum of 

 the Lyceum of Natural History, New York ; it is described 

 and figured by Harlan in his ' Medical and Physical Re- 

 searches,' p. 334, pi. xv. figs. 1-4 (1835), under the name 

 of Megalonyx laqueatus ; by Owen in the ' Zoology of the 



1 Zoology of the Voyage of the ' Beagle,' pt, 1, p. 68 (1840). 



2 Amer. Journ. ser. 1, vol. xliv. p. 69 (1843'i. 



8 Proc. Ac. Nat. Sci. Philad. vol. vi, p. 241 (1853; vol. dated 1854). 



