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Show 974 MR. ST. GEORGE MIVART ON THE LEMURIDJE. [Dec. 12, Galago. I find in G. crassicaudatus the dimensions to be as follows :- . . inches. Length of tibia 3*40 of tarsus 1 "65 of os calcis 1 '25 of cuboides 0*40 from proximal end of os calcis to distal end of cuboides 1 '50 - of astragalus 0*59 of dorsum of naviculare 0*71 Least transverse dimensions of both os calcis and na- . viculare 0*33 I am not disposed to consider the elongated tarsus of C. furcifer a sign of any really close affinity between that form and Galago; for a still more elongated tarsus distinguishes the genus Tarsius (remote enough from either Cheirogaleus or Galago), and the Cheiro-galei, so closely allied in other respects, differ greatly in the proportions of this part. Moreover the distinction as to geographical distribution between Cheirogaleus and Galago is very striking, although it may be remarked that C. furcifer is an inhabitant of the west coast of Madagascar. Finally, the difference which, according to Dr. Peters, exists in the position of the gall-bladder must not be forgotten. It is interesting to note the great variation as to tarsal structure exhibited by these nearly allied species from Madagascar, compared with which the differences exhibited by the various species of Galago are quite trivial. There are overwhelming reasons for believing that in Madagascar we are near (or at least probably nearer than in any other land now above the sea-level) to the locality where the original forms of the whole suborder Lemuridea first arose. Subsequent modifications, however, such as the exaggerated tarsus now found only in Africa on the one hand, or in Borneo and Celebes on the other, might have arisen in some more or less remote locality. The coexistence, however, of closely allied forms, in Madagascar, differing so much from one another in tarsal structure, seems to m e to indicate that this peculiar conformation of the tarsus (unknown in any other group of animals) also took its rise in the same region, and that modified descendants, diverging east and west, there carried still further this remarkable peculiarity, which culminates, and is accompanied by the maximum of lemurine abnormalities, in the most remote region to which any species of the Lemuroidea has, as far as yet known, ever extended. The inflation of the mastoidal region of the periotic, which causes Lepilemur to differ from the other Lemurinee, and assimilates it to Galago, is not, I think, a character of any great importance. It exists in the Nycticebince as well as in Galago ; and in the genus Lndris an enlargement above the posterior root of the zygoma (which seems to answer to the mastoidal swelling of Galago) is present in J. laniger, while it is absent in /. brevicaudatus*. * P. Z. S. 1866, p.J60. |