﻿14 



PLEISTOCENE MAMMALIA. 



(8) Measurements 



of the Deciduous Teeth (continued). 







Lower. 





Teeth in jaw from Kent's Hole, Tor- 

 quay, figured in PI. Ill, fig. 4 (Brit. 

 Mus. No. 1743). 



Teeth in jaw from Kirkdale Cave 

 (Brit. Mus. No. 36). 



d.m. 2. 



1-05 

 0-65 



0-65 



d.m. 3. 



d.m.' 4. 



2-1 



0-Y 



d.m. 2. 



d.m. 3. 



d.m. 4. 



Maximum anteroposterior measurement ... 



Maximum transverse measurement of crown 



Measurement from notch between roots to 

 top of crown 



1-45 



0-75 



0-8 



105 



055 



15 



07 



2'05 

 065 



c. The Vertebral Column (Pis. VI, VII, VIII). 



(1) Distinctive Features of the Vertebral Cchmnof tie Genus Hyaena. — There are not 

 many distinguishing features characterising the vertebral column in Hyaena as compared 

 with that in other Carnivora. Twenty is the regular number of thoraco-lumbar vertebras 

 in the great majority of Carnivora, but the relative proportion of thoracic to lumbar 

 varies from thirteen thoracic and seven lumbar in Felts, Cams, and Viverra, to sixteen 

 thoracic and four lumbar in Arctonyx collaris. In Hycena there are fifteen thoracic to 

 five lumbar vertebras. 



The small size of the thoracic vertebral centra, and the rapid decrease in the length of 

 the neural spines when followed back, are features characterising Hycena. The first 

 sacral vertebra is a good deal larger than the others, causing the sides of the pelvis to 

 converge posteriorly as in TJrsus, instead of being approximately parallel as in Canis. 



(2) Distinctive Features of the Vertebral Column in the Different Species of Living 

 Hyaena. — There seems to be no marked difference between the vertebral columns of 

 H. crocuta and H. striata, except that in II. crocuta the sacrum includes four vertebras, 

 while in //. striata there are three. There are only eighteen caudal vertebrae in 

 //. crocuta, as compared with twenty-three in H. striata. Most of the vertebrae are 

 more massive in II. crocuta than in //. striata, and the size of the vertebrae when 

 followed back decreases somewhat more rapidly in the former than in the latter species. 



