The Size of the Brain in the Insectivore Centetes

I DO not think that there is any recent mammal which has so small a brain in proportion to the size of the skull as has Centetes ecaudatus. In an individual of this species, the property of the Hon. Walter Rothschild, which was lately living in the Zoological Society's Gardens, I found the total length of the brain to be 28 mm., of which no less than 8 mm. were taken up by the enormous olfactory bulbs. The dried skull of that individual-measured along the base and not taking into account the projecting occipital region-was 96 mm. The greatest diameter of the brain is 16 mm.; the skull in that region is from 28 to 40 mm. broad. The small size of the brain relatively to the skull has been frequently commented upon and figured in certain of the early genera of Ungulate mammals; and it may be noted that the measurements which characterise Centetes, undoubtedly an early type of mammal, are by no means unlike those of such a genus as Coryphodon, judging, that is to say, by the published figures of the brain cast and skull of that animal. The resemblance is increased by the small size of the cerebral hemispheres, and by the complete exposure of the corpora quadrigemina in Centeles. I hope shortly to give a fuller and illustrated account of the brain of this Insectivore.