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Show 698 OR. C. I. FORSYTH MAJOR ON THE [June 1, Skin (M. 625), 2 • 145 94-5 13 27-5 20 18 Skin (M.628)(0*. 125 68 11 25-5 17 15-5 preceding species. The anterior one iu upper, the posterior one in lower molars being divided in the middle of the crown at an early stage of wear, the pattern presented in middle-aged specimens is the following :-a single enamel loop opening on the inner side of upper and on the outer side of lower molars; two on the outer side of upper and the inner side of lower molars. The single loops on the inner side of upper and on the outer side of lower molars remain open for a longer time than the others. Dimensions in millimetres, taken in the flesh : - Skin (M.516),$. Type. Length of head and body 142 tail 89 „ manus 12 „ pes 28 ,, ear 17'5 Breadth of ear - Loc. Ampitambe, outside the forest. Vinanitelo, close to the forest of the Independent Tanala of Ikongo, thirty miles south of Fianarantsoa. The specimens measured are from the former locality. Fossil in the Children's Cave near Sirabe ; abundant in the superficial, very rare in the lower deposits. The Affinities of the Genus Brachyuromys with Tachyoryctes, Ehizomys, Spalax, and Siphneus. 1. Tachyoryctes and Bhizomys.-With regard to the affinities of Brachyuromys, I made on a former occasion ' the following statement : - " The African and Asiatic Rhlzomyes, usually classed in the Spalacldce, but which Winge places amongst the lowest Murldce, alongside with the Tertiary Cricetodon and Eomys, are nearly related to the Malagasy group of Eodents by means of the Abyssinian Tachyoryctes (Bhizomys) and the Malagasy Brachyuromys, the former being but a very specialized fossorial form of the more generalized Brachyuromys ramlrohltra. The molars are almost identical in both, only slightly more hypsodont in Tachyoryctes." (They are much more so in the latter than in the former.) " If we divest the Tachyoryctes skull of its [excessive] fossorial characters and of the consequences of tbe more hypselodont molars, we obtain a Brachyuromys skull. Likewise the skulls of the young Tachyoryctes bear much greater resemblance to Brachyuromys than the adult. There is further a great correspondence in external characters if we disregard the smaller ears and eyes of Tachyoryctes and its fossorial claws." In the following I give the reasons for the above statements. In spite of all the differences of the skulls at first sight, a closer 1 P. Z. S. 1896, p. 979. |
