hay: on fossil \^rtebrates. 41 



mates on this width it is concluded that the carapace had a length 

 of about 340 mm. and a width of 290 mm. 



1^ As will be observed on the figures, the gular scutes extended 

 backward on the entoplastron. The humeropectoral sulcus bends 

 backward and again forward as it crosses the hjTDoplastron. This 

 forward cm've makes it probable that the sulcus crossed the hinder 

 end of the entoplastron, but this is not certain. Another sulcus 

 just outside of the axillary notch cut off an axillary scute. 



This tortoise is quite distinct from Gopherus polyphemus. It is 

 probable that a veiy large species, T. crassisaitata, inhabited 

 Kansas and the region further south during the early Pleistocene, 

 inasmuch as it occurs in Texas; but this was far larger, and the 

 bones described above give no indication of ha\'ing been those of 

 a young animal. 



Mylodon harlani Owen. 



In the collection are three teeth of a Mylodon which seem to 

 belong to the species named above. Cragin reported these as be- 

 longing to Megalonyx; but they certainly do not belong to that 

 genus. They were found four miles southwest of IMeade, Kan. 



These teeth are identified as the left fu'st and third upper teeth 

 and the right first of the lower jaw. They are all damaged some- 

 what and parts have been lost at some time since exhumation. 



The first upper tooth is shown on plate I, figm-e 4; and a section 

 is shown on the plate (pi. Ill, fig. 2). The present length of the 

 tooth, measui'ed along the greater curv^e, is 120 mm. Originally 

 it was somewhat, but not gi'eatly, longer. It will be observed 

 that it curv-^ed considerably in passing downward and forward 

 from the bottom of the socket. In section the tooth is broadly 

 oval, with the inner face somewhat flattened. The anteropos- 

 terior diameter is 21 mm.; the transverse, 17 mm. It will be seen 

 that this resembles closely the section of the first tooth given by 

 Cope (Proc. Amer. Philos."^Scc., vol. XXXIV, p. 459, pi. X, fig.l,o) 

 and reproduced by the present writer (Geol. Surv. Iowa, vol. 

 XXIII, p. 134, fig. 33). The grinding sui'face is concave from 

 front to rear and it slopes somewhat downward from the outer 

 side. 



The third upper tooth is here shown in section (pi. Ill, fig. 3). 

 The present height of the tooth is 70 mm., but it was originally 

 higher. The greatest diameter is 36 mm., the width across the 

 anterior lobe, 27 mm. The hinder lobe is 13 mm. thick. The 

 grinding surface shows two planes of wear, one on the broad an- 



