OCR Text |
Show 1890.] COLLECTED BY DR. EMIN PASHA. 449 were simply adult and young of the same animal. But in their skulls, as in other cases in the present family, the age characters are so slight and doubtful that one would at first sight say that the skull of b was that of an adult animal; and therefore that it could not possibly be of the same species as the very much larger one of a. Furthermore, b agrees in every respect, external and cranial (except that it has not the white frontal spot), with the type of Georychus albifrons, Gray, in the British Museum; and, on the other hand, a agrees in its skull and dentition with that of G. pallidus, Gr., which is unquestionably synonymous with Peters's Heliophobius argenteo-cinereus. The colour of 67. pallidus, and, so far as can be judged from the figure and description, that of H. argenteo-cinereus, is very much paler than either of Emin's specimens, and this by itself makes it doubtful whether the latter are certainly of the same species. Without further material, however, it would not be safe to separate them on account of their colour alone. But the difficulty arises owing to the number of the teeth. In Peters's examples, in the type of G. pallidus, and in a of the present collection there are either five or six cheek-teeth, as in typical Myoscalops, while in the G. albifrons and in 6 there are only three or four, as in Georychus. But the peculiar structure of the posterior palatal region is quite the same in both, as also are the proportions of the digits ; and I a m therefore induced for the present to look upon the two small specimens as merely younger examples of M. argenteo-cinereus, and to suppose that as they got older they would have developed more and more of their posterior molars. The peculiar way in which the teeth of Myoscalops succeed each other behind up to a total of six renders the true homologies of the four cheek-teeth of Georychus a little doubtful, and instead of there being three molars and one premolar as is ordinarily supposed, it seems possible that there are really three premolars and one molar, the two molars suppressed being those that only come up in extreme old age in the allied genus Myoscalops. Finally, should the difference in colour already referred to prove of specific value, the type of " G. pallidus" would fall under M. argenteo-cinereus, while the dark-coloured species would stand as M. albifrons, to which both of Emin's specimens would then be referable. 20. AULACODUS SWINDERNIANUS, Temm. a. Monda, Nguru Mountains. 21. PROCAVIA BOCAGEI, Gray. a. 2. Usambiro. 3/9/89. " Iride fusco-umbrina. Found on the rocky hills round Usambiro. Native name ' Pembe.' " - E . This is a very considerable extension of the known range of P. bocagei; but Dr. Emin's specimen agrees on the whole so fairly well with the Angolan examples in the Museum that I do not at present feel justified in separating it specifically. |