Peterson : Description of Stenomylus. 



289 



The posterior division of the transverse process terminates anteriorly 

 in a compressed and sharp ridge which continues forward a short dis- 

 tance on the external face of the anterior division of the process. 

 This character is less pronounced in Oxydaclylus and Lama huanaco. 

 There is no visible vertebrarterial canal piercing the pedicels, the 

 anterior portion of the neural canal being damaged in the region where 

 it would be located. 



The sixth cervical is nearly complete anteriorly, while posteriorly it 

 is represented only by the postzygapophyses. The neural spine of 

 this vertebra is of greater prominence than on the two preceding ver- 

 tebrae, but is relatively less developed than in Oxydactylus. The 

 zygapophyses face upward more obliquely than on the preceding 



Fig. 4. Sixth cervical vertebra of Sten- 

 omylus gracilis. Left side. Type No. 

 1610. i nat. size. 



Fig. 5. Sixth cervical vertebra 

 of Stenomylus gracilis. Anterior 

 view. Showing the vertebrarterial 

 canal. Type No. 1610. \ nat. size. 



vertebrae, and are also more expanded laterally. The transverse 

 process is broken off close to its base, but enough is preserved to show 

 that in relative size and position it is identical with that of Oxydac- 

 tylus. The lamella below the process is apparently fully as well 

 developed, pointing downward in its anterior region, and was perhaps 

 a thin plate of bone, as in Oxdactylus and Poebrotherium, while that 

 in Lama huanaco is distinctly divided into an anterior and a posterior 

 portion. The vertebrarterial canal is visible at the base of the pedi- 

 cle, as in Oxydactylus and the recent genera (see fig. 5). 



The greater portion of the seventh cervical vertebra is present in 

 the type. Its "neural arch is quite heavy, but the spine was evidently 

 comparatively small in proportion. The centrum is damaged anteri- 

 orly and posteriorly, but the transverse process of the right side is 

 present ; it is a heavy plate of bone, which apparently covered a con- 

 siderable portion of the lateral face of the centrum. There is no ver- 

 tebrarterial canal in the seventh cervical. 



