THE RABBIT. 285 



axial, somewhat flattened, and projecting beyond the first, 

 for the calcaneum ( 99). 



97. The femoro-tibial or semilunar cartilages, two thin plates 

 interposed between the femur and the tibia : their concave edges are 

 turned towards one another, and they are situated immediately beneath 

 the condyles of the femur. 



98. The fibula, a small rod of bone, attached by its 

 proximal end to the outer tuberosity of the tibia; distally 

 it fuses with the tibia at the middle of its length ; its proxi- 

 mal end is formed by an epiphysis. 



99. The tarsus, consisting of six irregular bones 

 arranged in three rows. In the proximal row are two bones, 

 the astragalus (tibiale), situated on the pre-axial side, and 

 having at its proximal end a large pulley-like surface for 

 articulation with the tibia ; and the calcaneum (fibulare), on 

 the post-axial side, having at about the middle of its length 

 an articular surface for the tibia, beyond which it is pro- 

 duced into the long calcaneal process, or heel. In the 

 middle row is the single navicular (centrale), articulating 

 chiefly with the distal end of the astragalus, but partly also 

 with the distal and pre-axial edge of the calcaneum ; its 

 ventral or plantar surface is produced into a large distally 

 directed process. In the distal row are three bones, the 

 mesocuneiform (tarsale 2) and ectocuneiform (tarsale 

 3), articulating with the navicular, and the cuboid (tarsalia 

 4 and 5), articulating chiefly with the calcaneum. The 

 entocuneiform (tarsale i), is either absent or is ankylosed 

 with the proximal end of the second metatarsal (see 100). 



100. The metatarsals, four in number, the first (that of 

 the hallux or pre-axial digit) being absent. The third is 

 the longest, the fourth the next longest, and the second and 

 fifth of about the same length. The proximal end of the 

 second (the apparent first) articulates with the mesocuneiform. 



