LEPUS 141 



transverse process of the vertebrae, and the capitulum of the 

 rib to the centrum. The thoracic vertebrae are usually a 

 dozen in number, and each is related to a pair of ribs with 

 which it articulates by tubercular and capitular facets. Behind 

 the thoracic region are the lumbar vertebrae, usually seven in 

 number, and characterised by their large transverse processes. 

 Next comes the sacral region which is attached to the ilium of 

 the pelvic girdle, and the caudal region with vertebrae which 

 become simpler in structure as they approach the tip. 



Fore Limb and Girdle. — The pectoral girdle is formed by the 

 scapula, which bears a ridge, the acromion, and a small coracoid 

 process representing the coracoid of lower forms. There is 

 no separate coracoid. The clavicle is slender, and joins the 

 acromion to the sternum. The arm is made up of the usual 

 bones : humerus, radius, and ulna, three proximal carpals 

 (scaphoid or radiale, lunar or intermedium, cuneiform or 

 ulnare) ; one central carpal (centrale), and four distal carpals 

 (trapezium, trapezoid, magnum, and unciform) make up the 

 wrist. There are five metacarpals, and the phalanges are 

 2, 3, 3, 3, 3 in number on the respective fingers. 



Hind Limb and Girdle. — The pelvic girdle is formed of the 

 usual three bones : ilium, ischium, and pubis, on each side. 

 The ilium runs forwards and upwards from the acetabulum to 

 the sacrum, instead of backwards as in reptiles. The pubis 

 meets its fellow from the opposite side in the middle line, 

 forming the pubic symphysis ; and a large obturator foramen 

 separates the pubis from the ischium of its own side. 



The femur has a large head, which fits into the acetabular 

 cavity of the pelvic girdle, and three processes or trochanters, 

 which serve for the attachment of muscles. The tibia is large, 

 but the fibula is small and fused on to the tibia. Covering the 

 front side of the joint between femur and tibia is a small bone, 

 the patella or knee-cap. 



The proximal tarsal bones are two in number : the astra- 

 galus, and the calcaneum (heel-bone). There is one centrale 

 or navicular, and three distal tarsals. The latter are, the 

 mesocuneiform (2nd tarsal), ectocuneiform (3rd tarsal), and 

 the cuboid (fused 4th and 5th tarsals). The rabbit is specialised 



