395 



presenting an articular surface (h) for the tarsal sesamoid, above which is a grooved 

 impress of a peroneal tendon. The distal joint (PL LXXV. fig. 13) at its upper half is 

 simply convex vertically, almost flat across ; but at the lower half there is a median 

 rising, or ridge (a), causing two lateral surfaces concave across, and affording a firm 

 trochlear joint to the proximal phalanx of the fourth toe (ib. figs. 16, 17). 



The fifth metatarsal (ib. fig. 2, v, fig. 14) is compressed to near its distal end, having 

 a sigmoid flexure vertically. The proximal articulation (ib. fig. 14) is an oblique flat 

 triangular surface for that marked I on the cuboides (ib. fig. 12). The distal articula- 

 tion (ib. fig. 15) is simply convex, and chiefly so vertically. 



The digits correspond in size with their supporting metatarsals. The two diminutive 

 inner ones terminate each in an unguiculate phalanx, and are enveloped as far as this 

 joint in a common sheath of tegument, from which the two small claws protrude; they 

 are applied to dressing the hairy integument of the Kangaroo. 



Of the first phalanx of the fourth toe an upper (ib. fig. 16), an under (fig. 17), and 

 a proximal-end view (fig. 18) are given. An upper view of the second phalanx is given 

 at fig. 19. The last phalanx of the chief toe (iv) is elongate and conforms to the long, 

 sharp-pointed, straight, three-sided, bayonet-like claw, which forms the chief weapon 

 of the Kangaroo. The broad underside of this claw rests, like a hoof, on the ground ; 

 the smaller sheath of the ungual phalanx of the fifth toe has a similar quasi-ungulate 

 character. 



DESCRIPTION OF THE PLATES. 

 PLATE LXVI. 



Figs. 1-5. Skull of Macropus rvfus. Fig. 6. Lower molars, left side, grinding-surface. 



PLATE LXVII. 

 Figs. 1-4. Atlas vertebra. Figs. 5, 6. Axis vertebra. 

 Fig. 7. Fourth cervical, upper view. 

 Fig. 8. Sixth cervical, front view. 



Fig. 9. Seventh cervical and first three dorsal vertebrae. Fig. 10. Last three dorsal 



vertebrae (d 11, 12, 13). 

 Fig. 11. First lumbar vertebra. Fig. 12. Third lumbar vertebra. Fig. 13. Fifth lumbar 



vertebra. 



PLATE LXVIII. 



Fig. 1. First rib. Fig. 2. Second rib. Fig. 3. Third rib. Fig. 4. Fifth rib. Fig. 5. 

 Tenth rib. 



Fig. 6. Manubrium sterni, outer or under surface. Fig. 7. Idem, distal end. 



Fig. 8. First sacral vertebra, front articular view. 



Fig. 9. First and second sacral vertebrae, neural surface. 



Fig. 10. Second caudal vertebra. Fig. 11. Id., haemal arch. 



