Mammalia. Hyracoidea. 43 



The Scapular Arch and Appendages. There is no po\rer of Eola- 

 tion of the Fore Limb in any Hoofed Quadruped. There are no 

 Clavicles. The Scapula is long in proportion to its breadth ; its 

 spine developes no Acromion : the Coracoid is a mere tuberosity 

 The Humerus is remarkable for the size and strength of the proximal* 

 tuberosities. The Os Magnum, and the Digitus Medius (iii.) which 

 it supports, are largely developed. 



Solidungula. The ulna, represented by its well developed olecranal extremity, 

 is confluent with the radius in its proximal moiety. Digits iv. and ii. are rudi- 

 mental, and digit iii. alone encased in a Hoof, 



Muitungi^la. The radius and ulna sometimes interlock, e.g. in Rhinoceros, 

 sometimes partially coalesce at their distal ends, e.g. in Tapims. Digits ii., iii., 

 and iv. are fully developed, and each encased in a Hoof. In Tapir, the first or 

 trapezial digit is the only one absent ; and that articulated to the Magnum, 

 answering to the third, is the largest, and of symmetrical shape ; the whole fore- 

 foot plainly showing the Perissodactyle type, though with four toes. 



Pelvic Arch and Appendages. The Ilium is generally rather 

 hammer-shaped, and articulates by its superior angle with two or 

 three of the sacral veitebra). The Ischium is produced backwards 

 considerably. The Femur has a third trochanter : and the medullary 

 artery penetrates the middle third of the back part of the shaft ; it 

 has no constriction between the head and shaft. 



Solidungula. The Jibula is as rudimentary as the ulna. 

 Multungula. ThQjibula is fully developed. 



IX. HYEACOIDEA. 



The SJcull. The elements of the Occipital bone are late in coales- 

 cing. An Interparietal is present in the back part of the sagittal 

 suture. The ascending process of the Malar articulates with the 

 post-orbital process which is formed by both Parietal and Frontal 

 bones. The Tympanic, which forms the Bulla Ossea at the basis 

 cranii, has not coalesced with the Petrosal. The hinder halves of 

 the Palatines enter into the formation of the Palato-Nares. The La- 

 chrymal canal commences by one or two foramina, protected by a pro- 

 cess. The Maxillary forms the floor of the orbit as in Perissodactyla 

 Multungula ; but the premaxillaries join the nasals. The Lower Jaw 

 is remarkable for the backward expanse of the ascending Ramus, 

 The Coronoid process is perforated lengthwise at its base. 



The Vertehral Column. There are not fewer than twenty-nine or 

 thirty Dorso-Lumbar Vertebrae : the Dorsals in their form and pro- 

 portions resemble^those of the Rhinoceros : the Metapophysis exceeds 



