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Show 1866.] MR. ST. GEORGE MIVART ON MICRORHYNCHUS. 165 proportion of the same bone to the radius is only 14'2 to 100, while in Indris it is 18 3. The femur is wanting in the specimen described ; but De Blainville says* it about equals the length of the tibia, which last is, as compared to the radius, as 149" 1 to 100, and is very much compressed laterally, and strongly concave on its peroneal side. The fibula is relatively, as well as absolutely, rather more slender than in Indris, and still more so than in Lemur. The tarsus differs from that of the last-named genus in its rather longer astragalus, in its relatively shorter cuboid, which, compared to the os calcis, is only 37'6 to 100, instead of 46'0 as in Lemur. Indris closely resembles Microrhynchus in this respect, as its cuboid is to its calcaneum as 38*6 to 100. The cuboid of M. laniger is also less deeply grooved for the tendon of the peronaeus longus than is that of Lemur. The metatarsals are absolutely and relatively longer than in that genus, that of the hallux greatly exceeding the os calcis in length, while in Lemur it does so very slightly. When, in the autumn of 1864f, I endeavoured to clear up some of the confusion existing with regard to certain kinds of Lemuridar, I regretted being able to say so little regarding the Indrisinar, no extracted skull of either Propithecus or Microrhynchus then existing in this country. From a consideration of the figures extant of the cranium of the last-named genus I ventured on a decided opinion that those had rightly decided who associated it with Indris, and that it could by no means be separated from that form and approximated to Galago. The examination of the specimen now described fully confirms this view ; indeed so numerous and striking are the points of resemblance between it and Indris that it is a matter of some difficulty to find % distinctive characters sufficient to justify even their generic separation. Unfortunately I have had no opportunity of examining any extracted cranium of Propithecus; but I strongly suspect that when obtained it will be found closely to resemble the two other genera of Indrisinar, as the dentition, as far as can be seen in the mounted specimens in the British Museum, so closely agrees with that of Indris. That subfamily may, I think, be characterized as follows :- iNDRISINcE. Characters}.-I. ^. C. ~. P.M. g§. M. g=30. Ears short; muzzle long, moderate or short; hind legs much longer than the fore limbs ; index very short, much shorter than * Loc. cit. t See Notes on the Crania and Dentition of the Lemuridcp, P. Z. S. 1864, p. 611. J The cranial, most of the dental, and some other characters are, of course, drawn from Indris and Microrhynchus only, and may have to be curtailed or modified when the structure of Propithecus is better known. § The immature condition of the teeth of Propithecus represented in M . de Blainville's plate led me, in 1864, to the conclusion that there are, as stated, two premolars and three molars on each side of each jaw. (See P. Z. S. 1864, p. 634.) |