246 PROCEEDINGS OF THE ACADEMY OF [April, 



On the mesial surface a well-marked calloso-margiual sulcus is 

 present, which comes to the surface and furrows Ihe hemisphere as 

 the cross sulcus between its anterior and middle thirds. A small cor- 

 pus callosum with its genu, the septum lucidum and fornix, a ventri- 

 cle containing a thalamus opticus and corpus striatum, an anterior 

 and middle commissure were present, the latter being veiy much 

 developed. The nates are larger than the testes. The pons varolii 

 is small. The vermis is large, but little separated from the lateral 

 lobes. The floculi are large and lodged in fossae of the periotic 

 bones. The brain of Galeopithecus differs from that of all other 

 mammals in its hemispheres being so small, and yet at the same 

 time being so deeply furrowed. In comparison with that of 

 affiliated animals, the brain of GaleojyithecKs is less developed than 

 that of lemurs, but more so than that of insectivores. There are, 

 for example, sulci present in the brain of the lemurs that are 

 entirely absent in that of Galeopithecus and vice versa. The corpus 

 callosimi is much more developed in the brain of the former than 

 in that of the latter. On the other hand, the number and depth 

 of the sulci in the brain of Galeopithecus are far greater than in 

 the brain of any insectivore. Indeed, sulci are absent in even 

 large insectivorous brains like those of Tupaia, Rhyncocyon, while 

 the corpora quadrigemina are uncovered in the latter. Of the 

 mammals with which Galeopithecus has been affiliated it resembles, 

 as regard cerebral characters at least, the Chiroptera most, the num- 

 ber and disposition of the sulci being the same in the brain of the 

 latter as in that of Galeojnthecus, though not so deep. On the 

 other hand, the olfactory lobes and corpora quadrigemina are 

 comjiletely covered by the hemispheres in the brain of Pteropus, 

 for example, and the corpus callosum is much more developed than 

 in the brain of Galeopithecus. The brain of Galeopithecus is 

 neither that of a lemur, insectivore nor bat, resembling, however, 

 that of the latter more closely than that of either the other two, 

 standing, indeed, somewhat midway between the Insectivora on the 

 one hand and Chiroptera on the other. 



The distribution of the nerves having been thoroughly descril^ed 

 by Leche,'" the author will not dwell upon this part of the economy, 

 but will merely call attention to one or two points of special inter- 

 est. The facial and third cervical nerves supply the nuiscles of the 



'» Op. cit., pp. 52-55. 



