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Show 530 MR. W. BATESON ON AN ABNORMAL FOOT OP A CALF. [June 20 I consider that for the present the following species only can as distinct:- 1. Cyanorhamphus ulietanus (Gm.). Society Islands. 2. C. erythronotus (Kuhl). Society Islands. 3. G. unicolor (Vig.). Antipodes Island. 4. C. novae zealandice (Sparrm.). New Zealand, Chathams, Auckland I. 5. 0. cooki (G. R. Gray). Norfolk Island. 6. G. subflavescens, Salvad. Lord H o w e Island. 7. G. erythrotis (Wagl.). Macquarie Is. and Antipodes I. 8. 0. saisseti (Verr. & Des Murs). New Caledonia. 9. C. cyanurus, Salvad. Kermadec Islands. 10. C. auriceps (Kuhl). New Zealand. 11. G. malherbei, Souance. South Island, N e w Zealand. 12. C.forbesi, Rothsch. Chatham Islands. Mr. W . Bateson exhibited an abnormal foot of a calf, which had been forwarded to him for examination by the kindness of Mr. W . L. Sclater. The specimen was a right fore foot, bearing three digits disposed almost symmetrically with regard to the axis of the limb. Of the carpus only the distal row remained, consisting of the usual two elements, a trapezoido-magnum and an unciform. External to the unciform the small rudiment, considered as representing the fifth digit, was of the usual size and proportions. The upper end of the metacarpal bone presented no peculiarity. Peripherally, however, instead of the usual two articular surfaces the metacarpal in this limb had three articular surfaces, all standing in the same plane as those of a normal limb. Each articular surface is well formed and has a large trochlear ridge. The central articular surface differs a little from the other two, being slightly crowded against the external one. In it also the trochlear ridge does not exactly divide the articular surface, but is rather nearer to the external side. With each of the three surfaces articulates a digit containing three phalanges of full length. Over each articulation is a pair of normal sesamoids, three pairs in all, instead of twro pairs. Each digit bears a hoof. The hoof of the middle digit is convex on both sides, but each of the lateral hoofs is convex on its outer side and concave on the side turned towards the hoof of the middle digit. The small accessory hoofs, the ergots oi French writers, are normal and stand in their usual positions with regard to the limb, one being above and slightly external to the metacarpo-phalangeal articulation of each of the outer digits. The limb is almost exactly symmetrical about a line taken through the centre of the middle toe. Each of the toes had well-formed flexor and extensor tendons. In the normal metacarpus of the Ox there is in the peripheral third a median groove of some depth, indicating the line of demarcation between the metacarpals III. and IV. It is in this |
