300 ' Annals of the Carnegie Museum. 



Transverse diameter of tarsus at proximal portion of cuboid 23 



Greatest length of calcaneum 60 



Length of tuberosity of calcaneum from sustentacular facet to the free 



end 38 



Antero-posterior diameter of calcaneum at the fibular facet 28 



Greatest height of astragalus , 30 



Greatest transverse diameter of astragalus 18 



Greatest antero-posterior diameter of astragalus 17 



Greatest length of the metatarsals 198 



Greatest length of proximal phalanx of third digit . .. 44 



Summary. 

 Having carefully compared the above described type with Oxydac- 

 tylus longipes and the recent camels, it is very plain that we are (1) 

 dealing with an animal which is descended from the early Tylopodan 

 stem and which (2) branched off in the Tertiary (perhaps in the late 

 Eocene) to form (3) one of the most curious combinations of charac- 

 ters yet discovered in the numerous genera and species representing 

 that family in geological times. The chief peculiarities are in the 

 cranial structure, which have already been discussed in the present 

 article and elsewhere, and are well shown in the accompanying illus- 

 trations and also on Plate XII of this volume. 6 The osteological 

 structure, outside of certain portions of the skull, is altogether more 

 nearly similar to that in Oxydactylus than the recent forms. In fact 

 were it not for the good fortune of finding the skull connected with 

 the rest of the type specimen I should perhaps not have ventured to 

 suggest a generic name, since the characters of the different bones of 

 the skeleton so much resemble the Miocene camels generally. That 

 the habits of this animal were different from those of most Miocene 

 camels is quite evident, judging from the cranial characters enumerated 

 above. It would seem that Stenomylus should be regarded as the type 

 of a new subfamily, the erection of which, however, would better be 

 postponed until a thorough systematic study of the whole group is made. 

 The type above described is of much interest and furnishes a very forci- 

 ble evidence of the attempt at survival of many diverging lines repre- 

 senting the Camelidse in the late Tertiary time. 



Carnegie Museum, Pittsburgh, Pa. 

 January 24, 1908. 



e On the legend of this Plate (XII) read % for " %." 



