8 MB, ST. GEORGE MIYART Olf THE 



circum-Sylvian convolutions, so that the Ichneumons seem to 

 exceed even the Dogs in their wealth of convolutions. In fact, 

 however, not only is there no really special resemblance between 

 the brains of Herpestes and Canis, but the brain is less convoluted 

 than might appear from what has been said; for all the convolu- 

 tions are narrow, single, longitudinal, and tend to be imperfectly 

 separate one from another, especially towards the hinder part of 

 the cerebrum*. 



In some species the Sylvian gyrus is more or less subdivided 

 both in front and behind the Sylvian fissure, and in otliers the 

 sagittal gyrus is divided by a more or less extensive longitudinal 

 groove. Thus it is that there may appear to be three, four, or 

 even five circum-Sylvian gyri. The parietal gyrus, however, is 

 never posteriorly subdivided as in the Dogs. One very marked 

 character which distinguishes the brain of Herpestes from the 

 brains of Nandinia, Paradoxurus, Arctictis, Cynogale, and Eu- 

 pleres is its large crucial sulcus, which is always plainly to be 

 seen, often rather forwardly situated, on the dorsum of the cere- 

 brum. Into this sulcus the calloso-marginal sulcus is continued 

 forwards, separating the hippocampal and sagittal gyri, as they 

 have always been separated in all the species we have yet consi- 

 dered, except the species of Felidae. 



Galidia. — The brain of this elegant little genus is a simplified 

 Herpestine brain, there being t but three circuin-Sylvian gyri 

 with a very large and conspicuous crucial fissure. The hinder 

 limb of the Sylvian gyrus is vertically grooved. 



Crossarchus. — The brain in this genus bears a large crucial 

 sulcus, into which the calloso-marginal sulcus is continued. The 

 Sylvian gyrus has its hinder limb twice as broad as its anterior 

 limb, and the former is furrowed by a longitudinal vertical 

 groove. 



Suricata. — The Suricate J has a brain which ig remarkable for 

 the great size of that part of the Sylvian gyrus which is pos- 

 terior to the Sylvian fissure. This fissure has the appearance of 

 being prolonged upwards, and then suddenly and much curved 

 backwards and downwards, causing that part of the Sylvian gyrus 



* See P. Gei'Tais, I. c. p. 132, and plates vi. fig. 10, vii. fig. 4, viii. figs. 6 &7, 

 and is. fig. 1. See also Krueg, I. c. plate xxxvi. 



t See P. Gervais, p. 131, pi. vii. fig. 3. 



I See P. Gervais, I. c. p. 133, pi. Tiii. figs. 5 and 5a; see also Ki-ueg, l. c. 

 pi. xxxyi. 



