57 



premaxillaries, in position, are close together, showing a very 

 narrow muzzle. 



The maxillaries have two well-developed canines, with 

 long, laterally compressed fangs, recurved and becoming cir- 

 cular in section at the crowns. The diastema between the 

 canine and the first premolar is proportionate to that in Pro- 

 canielus. 



Ithygrammodon cameloides, sp. nov. 

 Spec ific cha ractcr ist ics. 



T\\Q premaxillaries (See Plate X., Figs. 1-4) are long, with 

 a wide, strongly upward curving process ; from the premaxil- 

 lary symphysis to the third incisor, they increase in thick- 

 ness ; then narrow slightly to the maxillar}^ symphysis. The 

 upper margin of the process is smooth and narrow, curving 

 very gradually upwards ; while the lower margin runs more 

 abruptly up, giving to it a strongly pointed curvature. 



The outer surfaces are smooth and slightly convex ; the 

 inner are marked by a wide deep canal running from just 

 behind the premaxillarv symphysis into the maxilla. 



The great size of this groove may perhaps be a generic 

 characteristic ; as it is much larger than in Protolabis (Plate 

 X., Fig. 6), the modern camels, or any of the other ungulates, 

 recent or fossil, that have come under our notice. 



The premaxillaries do not co-ossify, as the spines are 

 smooth on their inner side. Just outside the spines, and in 

 front of the deep groove, the bones are marked by numerous 

 small pits for the attachment of the muscles of the upper lip. 



The portion of the maxilla in which the first premolar is 

 situated, shows that the maxillaries swell considerably on 

 their alveolar border; for the canine then narrow gradually 

 for the first premolar diastema ; then swell for its reception, 

 and become very thin in the diastema between the first and 

 second premolars. 



The Teeth.— \ f , C, -J, Pm. '-f , M. \ 



The incisors have quite deep fangs, are cylindrical in shape, 

 vertical in position, and have no basal ridge. 



The crown of the first is worn perfectly smooth, flat across 



