| OCR Text |
Show 454 PROF. W. II. FLOWER ON THE CRANIAL AND [May 16, am by no means disposed to underrate the testimony of many experienced field-naturalists on this subject. Such osteological evidence as we have upon the question, if applied to the genus Equus, would probably fail to distinguish the three well-recognized South-African species of Zebras. The results derived from the examination of these fifty-four skulls of Rhinoceros may be thus tabulated :- A. The adults with a single large compressed incisor above on each side, and occasionally a small lateral one ; below, a very small median, and a very large, procumbent, pointed lateral incisor. The post-glenoid and post-tympanic processes of the squamosal united below the external meatus auditorius. The posterior occipital surface sloping from below upwards and forwards, the crest being anterior in position to the condyles. Nasal bones pointed in front. A single nasal horn. Skin very thick, raised into strong, definitely arranged ridges or folds. R H I N O C E R O S , Linn. a. Larger size. Upper molar teeth with crochet and crista generally united, cutting off an " accessory " valley from the median sinus. Posterior end of vomer thickened and adherent. Mesopterygoid fossa and basi-occipital narrow. Hinder margin of palate regularly concave. Occipital surface high and narrow. Ramus of mandible high. 1. R. U N I C O R N I S , Linn.* R. indicus, Cuv. (R. A. 1817). R. stenocephalus, Gray (P. Z. S. 1867). b. Smaller size. Upper molar teeth without crista. Posterior end of vomer thin and free. Mesopterygoid fossa and basi-occipital broad. Hinder margin of the palate produced in the middle. Occipital surface broad and low. Ramus of mandible low f. 2. R. SONDAICUS, Cuv. (in Desm. M a m m . 1822). R. javanicus, F. Cuv. & Geoffr. (Mammiferes, 1824). R.floweri, Gray (P. Z. S. 1867). R. nasalis, Gray (P. Z. S. 1867). B. The adults with a single moderate-sized compressed incisor above, and a single, laterally placed, pointed, procumbent incisor below, which is sometimes lost in old animals. The post-glenoid and post-tympanic processes of the squamosal not meeting below the meatus auditorius. Occipital crest produced backwards so as to * Cuvier's names for this and the common African species are often preferred on the following grounds:-"The names of R. unicornis and bicornis, Linn., can be no longer retained, since more than one species is known, both of those with one and of those with two horns" (Van der Hoeven's Handbook of Zoology). But as a precisely similar objection can be raised against the names indicus and africanus, nothing is gamed by the change. t The differences in external appearance, and especially in the skin-folds, between R. unicornis and R. sondaicus are well seen in the figure published in the Society's 'Proceedings,' 1874, pl. xxviii.; also in two sketches in ' Nature,' April ytn, 1874, from the animals living in the Society's menagerie. |
