MAMMALIA. SUBUNGULATA. 363 



glenoid cavity for articulation with the mandible, and also 

 extends forwards so as to meet the lachrymal. There is an 

 alisphenoid canal. There are as many as twenty-one or twenty- 

 two thoracic vertebrae, and the number of thoraco- lumbar 

 vertebrae reaches twenty-eight or thirty. There are no clavi- 

 cles, and the scapula has no acromion ; the coracoid process 

 is, however, well developed. The ulna is complete. In the 

 manus the second, third and fourth digits are approximately 

 equal in size, the fifth is smaller, and the first is vestigial. 

 The femur has a slight ridge representing the third trochanter. 

 The fibula is complete, but is generally fused with the tibia 

 proximally. There is a complicated articulation between the 

 tibia and astragalus, which has a pulley-like proximal surface. 

 In the pes the three middle digits are well developed, but there 

 is no trace of a hallux, and the fifth digit is represented only 

 by a vestigial metatarsal. 



The only representatives of the suborder are some small 

 animals belonging to the genus Procavia (Hyrax), which is 

 found in Africa and Syria ; some of the species are by many 

 authors placed in a distinct genus Dendrohyrax. 



Suborder (4). AMBLYPODA 1 . 



This suborder includes a number of primitive extinct 

 Ungulates, many of which are of great size. Their most 

 distinguishing characteristics are afforded by the extremities. 

 In the carpus the bones interlock a little more than is the case 

 in most Subungulata, and the corner of the os magnum reaches 

 the scaphoid, while the lunar articulates partially with both 

 magnum and unciform, instead of only with the magnum. 

 In the tarsus the cuboid articulates with both the calcaneum 

 and the astragalus, which is remarkably flat. The manus and 

 pes are short, nearly or quite plantigrade, and have the full 

 number of digits. The cranial cavity is singularly small. 



1 See E. D. Cope, "The Amblypoda," Amer. Natural, 1884 and 1885. 



