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Show 676 MR. F. G. PARSONS ON THE [Noy. 20, describes the teeth; the latter figures the base of the skull in A. africana and A. macrura, and mentions several points by which they can be distinguished. The teeth of the animal I examined agree with Gray's description, except that I was unable to make out any folds on their hinder edge. The premolars were in the process of being replaced by the permanent teeth, and this process was much further advanced in the upper than in the lower jaw. As I believe that the date of the shedding of the milk-premolars is unknown, it may be worth recording that the following epiphysial lines could be distinctly made out:-tipper end of humerus, lower end of femur, tip of olecranon, lower end of radius, upper and lower ends of tibia, lower end of fibula, hinder margin of ramus of ischium. The epiphysis for the crest of the ilium had practically disappeared. Fig. 1. Base of Skull, showing the temporary premolar tooth being replaced by the permanent one. a. Permanent premolar. b. Temporary premolar. In addition to the points noticed by Gray and Giinther, which it is unnecessary to recapitulate here, there are one or two others which seem of value in distinguishing the skull. • In the first place, in A. africana the frontal bone projects forward as a triangular spine for some little distance between the nasal bones. This characteristic was noticed in six out of seven skulls of A. africana, while in only one out of four specimens of A. macrura was it present. All the other Porcupines which I have examined have a straight suture between tbe nasals and the frontal, |