124 ANATOMY OF THE WOOD EAT 



The lesser occur as very small processes at this point and are 

 so poorly developed that it is doubtful whether their ossi- 

 fication is complete. 



The hyoid of Teonoma is slightly the largest. 



Vertebral column 



The number of skeletons available are satisfactory for the 

 purposes of the present paper; but very few of them are 

 perfect in all respects. Some are without skulls, several 

 without feet, and others are disarticulated in varying degree. 

 Neither are the measurements absolutely trustworthy, for 

 the backbones are curved into various positions. In addi- 

 tion, the given length of any class of vertebrae, as the lum- 

 bar series, is not the real, but the apparent length, as meas- 

 ured upon the middorsal line of the visible portions of the 

 vertebrae concerned. 



There are but three skeletons of Homodontomys, three of 

 Neotoma, and two of Teonoma in such position as to render 

 the taking of vertebral measurements entirely satisfactory. 

 For our purpose the measurement of total length is not as 

 desirable as that of the skeletal body length, comprising the 

 sum of the cervical, thoracic, lumbar, and sacral vertebrae 

 series. 



Cervical vertebrae 



There are seven cervical vertebrae, as usual, including 

 atlas and axis. In Homodontomys this series has a length of 

 20, 18.4, and 18 nun. respectively, or 13.7, 13.3, and 13.7 

 per cent of the vertebral body length. In Neotoma these 

 figures are 13.9, 14, and 13.3 mm., or 12.7, 13.2, and 12.6 per 

 cent of the body length; and in Teonoma, they are 20.4 and 

 17.7 nam., or 13.9 and 12.9 per cent. (In Neotoma I. stephensi 

 this percentage is 15.5, and in N.f. rubida, 15.1.) 



The atlas, articulating with the skull, is moderately 



