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Show 1867.] MR. ST. GEORGE MIVART ON INDRIS DIADEMA. 255 by the three forms (which I consider together constitute but a single genus) may perhaps be expressed as follows:- INDRISINCE. INDRIS. I.*=*. C.g. P.M.t-*. M.|3 = i" = 30. Characters.-Ears short; muzzle moderate, or rather or very short; hind legs much longer than the fore limbs ; index very short, much shorter than the fifth digit; pollex short and placed far back; hallux very long and covered with hair ; tail long, or very short and rudimentary ; internal condyle of the humerus perforated; carpus destitute of an os intermedium ; tarsus short; first upper molar with four principal cusps, and from two to four supplementary ones ; last upper molar with only two well-developed cusps ; each lower incisor with its outer surface longitudinally grooved; posterior lower premolar much antero-posteriorly extended ; first lower molar with five more or less distinct cusps ; last lower molar quinquecuspid ; a paramastoid process ; no malar foramen ; lachrymal foramen very near the margin of the orbit; a process depending from zygoma in front of, and external to, the glenoid surface; a glenoid foramen ; anterior palatine foramina very large ; mandibular symphysis very long ; condyle rounded, but very little transversely extended; articular surface prolonged somewhat down the back of ascending ramus; digastric fossa more or less deep. Hab. Madagascar exclusively. INDRIS BREVICAUDATUS. Characters.-Ears exserted ; muzzle moderately long ; tail short; posterior pair of upper incisors not much larger, sometimes decidedly smaller, than anterior pair ; upper canine longer than first premolar; skull not concave between the orbits ; antero-posterior extent of the anterior opening of the orbit less than the length of the muzzle in front of that opening; no protuberance above the external auditory meatus ; no process of the malar projecting over the anterior end of the zygomatic process of the squamosal; floor of orbit considerably above the upper alveolar margin ; a large palatine foramen behind the third molar; palate with its posterior margin thickened; mandibular symphysis much less than three times the length of the lower incisors; fossa for digastric not very deep; posterior part of articular surface of condyle not grooved, nor always much flattened ; angle very much bent downwards, making the inferior margin of the mandible exceedingly concave. Hab. Madagascar, but not St. Mary's Island. INDRIS DIADEMA. Characters.-Ears short, in the fur; muzzle rather short; tail long; posterior pair of upper incisors much smaller than the anterior pair ; upper canine larger than first premolar ; last upper molar very small; skull not concave between the orbits; antero-posterior |