HIGH SCHOOL ZOOLOGY. 151 



ffrounJ than in the cats, which are on this account called 

 digitigvade. The terminal joints of tlie toes in the cat-tribe 

 are attached in such a way, that, when not in use, the claws 

 M hich they bear do not touch the ground ; they ara retracted 

 into a sheath and are thus always kept sharp. In all the forms, 

 the skin underlying the portions of tlie feet which touch 

 the gi-ound is converted into pads or balls, the thickened 

 epidermis of which affords protection to the underlying cutis, 



8. A comparsion of the relative weight of the brain and body 

 in the cat with that in any of the lower classes of Vertebrates 

 will convince us that a great advance in intelligence is to be 

 expected, and, indeed, the relative size of the brain-case and 

 facial region in the skull already discloses its superiority in 

 tills respect. At first sight it may he difficult to compare the 

 cat's brain with that of any of the lower forms studied, for cer- 

 tain of the regions which are visible in the reptile or bird are 

 hero concealed by the overgrowth of other regions. This is 

 especially true of the thalamencephalon and the 0[)tic lobes, which 

 are entirely hidden by the backward extension of the cerebral 

 hemispheres. The cerebellum also has gained in size, especially 

 its latei-al loV)es, which are joined by a series of fibres crossing 

 transvei-sely under the fore part of the hind brain, and consti- 

 tuting the pons Varolii. In front of the pons, the fibres which 

 ascend through the medvilla oblongata towards the cerebrum 

 diverge in two masses, the crura, to the hemispheres, and in 

 front of the crura is the only part of the thalamic region which 

 i-eaches the surface of the brain, viz. the hypophysis and in- 

 fundibulum. On the whole, the most important changes are 

 those which have taken place in the cerebrum, for not only has it 

 increased in size by growing forward, backward and towards the 

 sides, but the grey matter of its surface, instead of being smooth, 

 is folded inwards in such a way as to leave a series of fissures on 

 the surface of the cerebrum with intervening convolutions. We 



