496 MR. R. LYDEKKER ON SCELIDOTHERIUM. [NoV. 16, 



S. bravardi. Should, howeTer, any of my fellow workers be able to 

 identify it with either of such forms, I shall be only too happy 

 to relegate this name to the rank of a synonym. 



The structure of the astragalus of S. bravardi (as Dr. Burmeister 

 remarks in his description of the larger form which I provisionally 

 associate) approximates very strongly to that of Megatherium, 

 although wanting the articular cup for the navicular ; and it is there- 

 fore probable that the hind foot of this species was more everted 

 than in S. leptocephalum. The shorter nasals of the present species 

 also diverge less widely from the Megatherium type than do those of 

 the last-named species, and this character is still more developed in 

 the following form. 



SCELIDOTHERIUM CHILIENSE, n. Sp. 



The form to which I propose to apply the above name is repre- 

 sented by a series of specimens purchased during the present year 

 by the British Museum, from a gentleman residing at Lima, which 

 were obtained from the Pleistocene of Tamarugal, in the district of 

 Tarapaca in Chili'. The specimens comprise three more or less 

 imperfect crania, the anterior portion of a mandible, and a consider- 

 able number of vertebrae and Hmb-bones. All that I have to say in 

 regard to the limb-bones is, that the astragalus is intermediate in 

 structure between that of S. leptocephalum and that of S. bravardi, 

 and that the humerus has a well-defined entepicondylar foramen. 



The least imperfect of the three crania is represented in Plate 

 XLVIII., and shows nearly the whole of the nasals. The most 

 striking feature of this cranium is the extreme shortness and breadth 

 of the latter bones — their length not exceeding one third of the total 

 length of the cranium — while the mandibular symphysis is also 

 equally short, as will be seen by the following measurements. That 

 this form is totally distinct from 8. leptocephalum is self-evident. It 

 appears more nearly allied to S. bravardi, with which it agrees in the 

 prominence of the lachrymal, the narrowness of that portion of the 

 maxilla appearing on the frontal aspect, the straight facial profile, 

 and the narrowness of the interdental portion of the palate ; but 

 differs by its greater width, by the still shorter facial portion, by the 

 probable abortion (as will be shown below) of the premaxillse, and 

 by the shorter anterior portion and symphysis of the mandible. 

 The mandible is quite unlike that of S. tarijense^, in which the 

 symphysial part is bent upwards very suddenly, nearly the whole of 

 it being above the level of the dental alveoli. The nasals of that 

 species are also much longer than those of the present form. 



With the skull of the so-called Platyonyx brongniarti from Brazil, 

 figured by Lund in the K. Danske Vid. Selsk. Skr. vol. ix. pi. 

 xxviii., the present specimens agree very closely in general characters ; 

 but in addition to being of superior size, the cranium is relatively 

 narrower, and lacks the marked expansion behind the nasals, while 



'^ See map, supra, p. 396. 



^ I refer to this species a left mandibular ramus from Brazil in the British 

 Museum (No. 18649 a). 



