54 Mammalia, MarsupiaUa. 



only in the aged. In the Lumbar vertebrae the metapophyses attain a 

 great size. The number of vertebrse succeeding the lumbar, which 

 are anchylosed together in the Sacral region of the spine, varies 

 from seven, in "Wombat, to one, in Perameles: usually but one 

 vertebra supports the iliac bones. In most of the Marsupialia 

 which have a long Tail, whether used to support or suspend the 

 body, Y-shaped bones are found beneath the articulations of 

 most of the caudal vertebrae, which serve to protect the blood vessels. 



The Scapular Arch and Appendages. The Scapula varies in 

 form ; the coracoid exists as a process of the scapula, being anchy- 

 losed with it, as in the higher Mammalia, and not articulating with 

 the Sternum. The Subscapular area is generally more or less convex, 

 or undulating. The Clavicles are present in all except Perameles and 

 Chaeropus (?) ; are strongest and longest in the buiTOwing Wombat, 

 weakest and shortest in the great Kangaroo. In almost all, the in- 

 ternal condyle of the Humerus is perforated. The Radius and Ulna are 

 always distinct and well developed, but run nearly parallel and 

 lose together. The olecranon is always well developed. There 

 is not any digit situated like a thumb, but all the fingers enjoy lateral 

 motion, and those at the outer side can be opposed to those at the 

 inner side, so as to grasp an object. The long ungual phalanges of 

 the Peramelidae are clelt mesially. Chaeropus has a manus much 

 resembling that of the Artiodactyla, but differing from it in having 

 digits ii. and iii. functional instead of iii. and iv. 



The Pelvic Arch and Appendages, &c. The Pelvis in the mature 

 Marsupial is composed of the os sacrum, the two ossa innominata, and 

 the characteristic supplemental bones attached to the pelvis, called 

 the ossa Marsupialia ; these last being ossifications of the internal 

 tendon of the external oblique muscle of the abdomen.* The length 

 of the symphysis of the Ischia (or the lower part of what is commonly 

 called the symphysis pubis), and the straight line formed hy the lower 

 margin of the Ischia, is a characteristic structure of the pelvis in most 

 Marsupialia. The shaft of the Femur presents no linea aspera, the 

 head is supported on a very short neck. The internal Malleolus is very 

 slightly produced in any Marsupial. The Fihula is well developed. 

 In the Scansorial and Gradatorial Marsupialia the bones of the 

 anterior and posterior extremities are of nearly equal length ; but 



* These bones have no special function relating to the ventral pouch of the 

 female, being nearly equally developed in both sexes, and also in those species 

 in which the Marsupium is not present. Flowtr. 



