32 



TIIO^MAS DWTOTTT OX 



human than those of "Sally" which iire prolonged further upwards away from the 



head. In " Gumbo " tlie two are very unlike. 

 Their proportions differ considerably. The right 

 one is 8 cm. long by 6 cm. l)road, while the length 

 of the left is 8.7 cm. and its breadth 5 cm. The 

 length in the T. mibryi is 7 cm., that of "Mr. 

 Crowley's," taken from a cast, is 9 cm. and the 

 breadth 5.5 cm., that of " Sally," taken from the 

 life-size illustration, is length, 7.6, breadth, 5.3 cm. 

 In " Gumbo " tlie notch is well marked on both 

 sides, but narrower in the narrow left ear. There 

 is a very rudimentary lobule, stronger on the left. 

 This is present in the T. aubryl, and quite wanting 

 in " Sally." The ascending part of the helix of the 

 left ear folds over much more strongly than on the 

 right, but the fold is interrupted at the top on the 



Eight Ear. 



left, while in the right it is continued into the pos- 

 terior border. After this interruption, however, the 

 fold of the helix along the Ijack of the ear is stronger 

 on the left than on the right. 



It would be presumptuous to dispute with the 

 distinguished authorities who declare that there is 

 more than one species of chimpanzee. There can be 

 no question, however, that the range of individual 

 variation is very great in the details of the skeleton, 

 of the muscles, and of the brain. It has not seemed 

 advisable to publish a full description even of those 

 parts of this animal which could be thoroughly 

 studied. In this paper particular attention is given 

 to the brain and to peculiarities in tiie muscular 

 system of the extremities. 



The Age. 



Left Ear. 



According to very vague information which I have received, this animal was ten or 

 twelve years old. " Sally," who lived more than eight years at the zoological gardens in 

 London, was thought to be about two years old when she came. The chief criterion of 



