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Show 176 PROF. W. H. FLOWER ON THE MUSK-DEER. [Mar. 16, upper surface of the brain, together with a narrow strip (fig. 11, oi the internal or hippocampal gyrus. In the Mexican Deer the sulcus certainly rises quite to the upper edge of the internal surface of the hemisphere ; but neither in this species nor in tbe Roe (according to Leuret's figure) is any part of the hippocampal gyrus exposed near the middle line. What makes this character interesting is Fig. 13. Internal surface of cerebral hemisphere, natural size. h, hippocampal gyrus. that in Tragulus it is present even to a greater degree, the hippocampal gyrus bordering the posterior half of the great longitudinal fissure forming a prominent feature in the upper surface of the brain. In other respects the brain of Tragulus, as far as its surface-markings are concerned, is a simplified miniature of that of the Cervida. The inferior external longitudinal convolution is distinctly marked from the superior ; but the latter bas scarcely a trace of a division into two, though at first sight the abnormal position of the calloso-marginal sulcus might be taken for one. Whether this is any special evidence of affinity between Moschus and Tragulus, cannot be decided until the brains of other small species of Cervida have been examined. In the mean time, I can only point it out and await future opportunities of investigation. The comparison of cerebral convolutions as evidence of affinity is a subject iu which, without very careful or extended research upon ample materials, the investigator is apt to be led astray, but one which, under favourable conditions, may lead to valuable results*. * The opportunity of examining the brain of the Pudu Deer has afforded tbe means of solving the question stated above. It is slightly larger, both relatively and absolutely, than that of the Musk, as the following dimensions show:- Moschus Cervus moschiferus $ . humilis J. Length of skull from front of prsemaxillse to occipital in. in. protuberance 6*1 5*8 Length of cerebral hemisphere 21 2-4 Greatest breadth of cerebral hemispheres 1-7 1*8 It is chiefly distinguished by the greater breadth of the frontal lobes (see |