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Show 254 MR. ST. GEORGE MIVART ON INDRIS DIADEMA. [Mar. 14, inch. Length between vertical planes traversing the most anterior and most posterior points of orbital margin 0*46 Length from orbital margin to posterior end of skull 1*66 Extreme width between outer margins of orbits.... 1*81 Extreme width behind posterior roots of zygomata. . 1 *49 Width between nearest points of orbits 0*61 Length of palate 1 *20 Breadth of palate between first premolars . 0*45 Breadth of palate at its posterior end 0*63 Length of nasals 0*65 Breadth of nasals 0*34 Length of lower alveolar margin from front of first premolar to behind last molar 1*15 Length of symphysis 0'80 Height of condyle above alveolar margin 0*43 Height of coronoid process above alveolar margin .. 0*70 Of the rest of the skeleton of 7. diadema I am entirely ignorant; but I have no doubt that when examined it will show an agreement with the skeletons of the two other species, similar to that which exists between their crania and dentition. As I have before observed, I feel convinced that sufficient grounds do not exist for the generic separation of the species now described, the Woolly Lemur, and the Short-tailed Indri. The dental characters are all but identical; and as regards the crania the main distinctions are those of the size of the entire skull, the proportional length of the muzzle, and the development of the orbit-characters which in other genera of Primates vary considerably amongst species of the same genus, especially when such genus contains species of very different dimensions. The tail is short indeed in I. brevicaudatus, as compared with the same part in either of the two other species ; but length of tail varies much in Macacus and Cynocephalus, especially if, as I believe should be the case, M. inuus be included in the former genus. The posterior incisors in 7. diadema are decidedly larger than the anterior pair, while the reverse is the case in 7. laniger ; but, as before observed*, 7. brevicaudatus appears to be subject to some variation as to the relative size of the two pairs of upper incisors. The shortness of the upper canine in 7. laniger distinguishes it (as far as m y observations have gone, and judging from De Blain-ville's figure) from the two other Lndrisince; but Prof. Van der Hoeven's figuref and that of Prof. Vrolik "j: leave it doubtful whether this is not merely a sexual peculiarity. In other points given in m y former paper as characters distinguishing 7. laniger from 7. brevicaudatus, we have seen that 7. diadema presents an intermediate condition ; and the characters offered * P.Z. S. 1866, note in p. 154. 1* Loc. cit. pl. 1. fig. 6. \ Todd's ' Cyclopaedia,' iv. p. 215. fig. 136. |
