47 PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



the rodents, and has an extensive lateral contact with the ectocuneiform ; 

 on the tibial side is an oblique bevelled surface for the entocuneiform, the 

 shape of which makes it probable that no vestige of the hallux was retained. 

 The shaft is slender, subtrihedral and curved, with concavity toward the 

 tibial side, expanding slightly toward the distal end. 



Metatarsal III is the longest and heaviest of the series and its apparent 

 length is increased by its position in the foot, the proximo-distal length 

 of the ectocuneiform so much exceeding that of the mesocuneiform, on the 

 one hand, and that of the cuboid on the other. The tarsal facet is nearly 

 plane and horizontal, without obliquity ; the shaft is straight, broad and 

 antero-posteriorly compressed, widening somewhat to the distal end ; the 

 trochlea is low, shorter proximo-distally than in Dolichotis and the supra- 

 trochlear fossa is smaller. Metatarsal IV is the counterpart of II in size 

 and shape, but is somewhat more curved ; on account of the extreme 

 shortness of the cuboid, the head of this metatarsal rises higher above that 

 of III than in the modern genus. On the fibular side of the head is a 

 large depression and a very small articular surface, evidently for the rudi- 

 mentary fifth metatarsal and, no doubt, this rudiment had much the same 

 shape and relative size as in Dolichotis. 



In proportion to the length of the metatarsals, the phalanges of the first 

 row are more elongate and slender than in Dolichotis, though, like all 

 parts of the limbs and feet, they are smaller in comparison with the head 

 and vertebral column. The unguals are quite different from those of the 

 recent genus, being more curved, slender and sharply pointed, with smaller 

 distal cleft, and altogether more claw-like ; the subungual process is very 

 large and prominent. 



Restoration (Plate LXXI). The resemblance between the skeleton of 

 Eocardia and and that of Dolichotis is obvious at the first glance, but 

 there are many minor differences in all parts. The skull has a shorter, 

 thicker and wider rostrum, and the symphysial region of the mandible is 

 less procumbent. The neck is shorter and lighter and in the trunk the 

 vertebral column has quite a different curvature, owing to the greater 

 disparity in length between the fore and hind limbs, while in the lumbar, 

 sacral and caudal regions the neural spines are shorter and much more 

 slender. The tail is somewhat longer and thinner, and the ribs are 

 thinner and less plate-like, making a smaller and lighter thorax. The 

 limbs are much shorter and the feet smaller and, in particular, the fore 



