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Show 36 SIR V. BROOKE ON THE GENUS CERVULUS. [Jan. 6, bones-the astragalus (Astr), the confluent navicular and cuboid bone (N & Cub), that of the second and third cuneiform (3, 2), and the first cuneiform (1). In the adult tarsus of Cervulus (fig. 1 d), in several specimens which I have examined, there are but four separate bones; these bones are the calcaneum, the astragalus, and then a large nearly square bone (fig, 1 d, Cub, N, 3, 2) with a small space cut out of its interno-posterior surface for the reception of a very small bone (fig. Id, 1), which appears, from its relation to the surrounding parts, unquestionably to represent the first cuneiform. Nor can there, I think, be much doubt that the large square bone of the tarsus of Cervulus represents the naviculo-cuboid bone of the ordinary Pecora, plus the confluent second and third cuneiforms. The order of the successive steps of the anchylosis of these separate parts appears to me of considerable interest; I find in the skeleton of the very young specimen of Cervulus sclateri above mentioned (fig. 1 e), that the distal row of the tarsus consists of two nearly equal-sized bones (Cub & N, 2, 3), and the very small first cuneiform (I). Anchylosis appears to be just commencing between the two larger bones. In the skeleton of a Fallow Deer of similar age (fig. 1 / ) the navicular and cuboid present a condition similar to that exhibited by these two large bones in the tarsus of Cervulus. It would therefore appear that the unusual condition of the anchylosis of the navicular and confluent second and third cuneiforms obtains in Cervulus at an earlier age than the ordinary condition, amongst the Cervidse, of the confluence of the navicular and cuboid bones. An interesting question naturally follows, and one which palaeontology will doubtless one day answer. Is the history of the tarsus of the individual an epitome of that of the entire form ? If so, Cervulus and Cervus will be found segregated far into the geological past 5 and in considering the genealogy of the latter, no species need be taken into consideration that exhibits the cervuline tarsus-the converse obtaining with equal force, no species presenting a cervine tarsus being likely to have held a place in the pedigree of Cervulus. The tarsus of Cervus pudu resembles that of Cervulus. In Hyo-moschus the second and third cuneiforms are either suppressed or anchylosed to the proximal end of the third metatarsal. In the Cervidse the reduction of the second and fifth metacarpals appears to have followed two distinct paths. In one the reduction takes place from above downwards, the proximal ends of these bones disappearing, the distal ends remaining articulated by synovial joints with their respective phalanges (fig. 2 a). Following this method I have observed Alces, Rangifer, Moschus, Hydropotes, Cervus capreolus, Coassus, Cariacus, and Cervus pudu. In the other, reduction appears to have crept from below upwards, the proximal ends of the bones remaining separated consequently from their phalangeal extremities (fig. 2 b). Following this second method are Rusa, Hyelaphus, Cervus dama, Cervus magaceros, Cervus ela-phus and its allies, Elaphurus davidianus, and Cervulus. Cervulus, however, in this respect (see fig. 2, c), as well as in the condition of the tarsus, shows an advance in specialization, all the phalanges of |
