1867.] PROF. ALLMAN ON POTAMOGALE VELOX. 257 



formula of this animal as given by Prof. J. V. Barboza du Bocage * and 

 that in the formula given by myself, the Lisbon zoologist describing 

 ten teeth on each side in both jaws, while in my specimen only nine 

 were apparent on each side. Mr. Mivart, however, thought that he 

 saw indications of a tooth still confined within the mandible at the 

 extreme posterior end of each ramus, while a small, apparently frac- 

 tured, surface in the corresponding part of the maxilla appeared to 

 afford evidence of a portion of the upper alveolar margin with its 

 tooth having been here carried away. 



I have now the satisfaction of being able to confirm in great part 

 the suspicion of Mr. Mivart. In the case of the mandible, it was 

 easy enough to set the question at rest. On removing a portion 

 of the side of the mandible, where the missing tooth was supposed 

 to be concealed, a small cavity was exposed, in which, with some 

 care, a minute calcareous point, the commencing calcification of 

 the dental papilla, still enveloped in the remains of its capsule, was 

 detected. 



There can thus be no doubt of the presence of a rudimental tooth 

 on each side in the mandible of my specimen, behind the most pos- 

 terior of those previously described by me. 



Of the existence of a corresponding tooth in the maxilla, no such 

 direct evidence can be adduced. There is certainly a very small 

 rough surface at the most posterior end of the alveolar "margin at 

 each side, and I agree with Mr. Mivart in thinking it probable that 

 a portion of this margin has been here broken off; the missing 

 fragment, however, must have been extremely small, and the tooth 

 which it contained must have been in at least as rudimental a state 

 as that of the mandible. 



Had I become acquainted with Prof. Du Bocage's determination 

 of the dental characters of Potamogale before my own communica- 

 tion had been printed, I should perhaps have made a search in the 

 same direction for the missing teeth ; but as it was, my specimen 

 gave me no reason to suspect that it did not offer an exposition of 

 the complete series, though it is now plain that it had not yet deve- 

 loped its last molars. 



The facts now stated render necessary a correction of the formula 

 which I had already given as that of the teeth of Potamogale, and 

 which must henceforth be regarded as applying to the dentition of 

 this genus before the adult state had been attained in the develop- 

 ment of the last molars. In the corrected formula the incisors and 

 premolars must remain as before, but to the true molars one must 

 now be added. The dental formula, as amended for the adult, will 

 accordingly stand as follows : — 



I-S- C.S. P.g. M.J3 = 40. 



PS. Since the above note was communicated to the Society, I 

 have been enabled, through the kindness of M. Jules Verreaux, of 



* Noticia acerca los Caracteres e AfBnidades Naturaes de un novo Geriero de 

 Manimiferos Insectivoros. Lisboa, 1865. 



Proc. Zoo£. Soc— 1867, No. XVII. 



