QUADKUMANA. MAMMALIA. - 



JALEOPITHECID.E. 



THE AYE- AYE (Cheiromys madagascariensis), fig. 

 7, the only known species of this family is, as implied 

 by its specific name, a native of Madagascar, where it 

 was first discovered by the celebrated French traveller 

 Sonnerat. The name, Aye-aye, conferred upon it by 

 him is said to have been borrowed from the expressions 

 of surprise uttered by those natives to whom he showed 



Fig, 7. 



teeth 



The Aye-Aye (Cheiromys Madagascariensis). 



his specimen, and who had never seen such a creature 

 before ; it was, however, supposed by him to be the 

 native name of his new-found treasure, and is now 

 generally received as the name of the animal. 



In its general appearance the aye-aye is intermediate 

 between the galagos and the squirrels, with the latter 

 of which animals it is placed by those zoologists who 

 refer it to the Rodentia. When adult it measures about 

 eighteen inches in length, and its tail almost as much 

 more. It is clothed with a thick fur composed of two 

 kinds of hair ; a thick woolly down close to the skin, 

 and longer smooth hairs, which form the outer coat. 

 'The general colour of the fur is a pale rusty brown, 

 with the face and throat lighter ; the tail is bushy, and 

 the ears -very large and naked. But the most remark- 

 able characters of the animal are, as may be supposed 

 from its doubtful position in the system, to be sought 

 in its structure. The dentition, which, as a general rule, 

 may be regarded as the best character by which to 

 determine the systematic position of a mammal, would 

 seem to indicate the justice of placing the aye-aye 

 amongst the rodents; the incisor teeth, as in those 



animals, are two in number in each jaw, long, stout, 

 and chisel-like, and the canines are altogether deficient; 

 but the molar teeth, four in the upper and three in the 

 lower jaw, although arranged in the same way as in the 

 Rodentia, present certain characters which are not 

 usual in that order. The skull, in its form, has some 

 analogy with that of the galagos, and the bony orbits 

 are complete a character which does not occur amongst 

 the rodents. 



Thus the characters to be drawn from the head and 

 leave the true position of the aye-aye still very 

 doubtful, and it is only from the structure of 

 the members that we are induced to place 

 this animal with the Quadrumana. The bones 

 of the forearms are distinct throughout their 

 whole length, and both these and the bones 

 of the wrist resemble those of the lemurine 

 animals. The forehands, however, are very 

 peculiar hi their structure, the thumb is not 

 opposable, the fingers are exceedingly long 

 and thin, the fourth being the longest, and 

 the third the thinnest ; all are terminated by 

 large nail-like claws. In the hinder-hands, 

 on the contrary, there is a distinctly opposable 

 thumb, and the claw of the first finger is 

 evidently more elongated and awl-shaped 

 than those of the others, in the same way as 

 in the true lemurs. Another singular char- 

 acter is the position of the teats, which are 

 situated on the groin. 



The aye-aye would appear to be rare even 

 in its native forests; only three specimens 

 have been brought to Europe, and these are 

 in the museum of the Jardin des Plantes at 

 Paris. This rarity may, however, be due to 

 the habits of the animal, which is a strictly 

 nocturnal creature, sleeping during the day 

 concealed in holes in the ground. It is 

 described as being exceedingly sluggish, but 

 we still know little or nothing of its general 

 habits and food. According to Sonnerat 

 it is insectivorous, and employs its long fingers in 

 drawing larvae from their holes in the trees ; but the 

 specimens which lived for two months in his possession 

 were fed with boiled rice, which they took up with 

 their hands, " using the slender fingers," as Sonnerat 

 expresses it, " in the same way that the Chinese 

 employ their chop-sticks." Other writers have sup- 

 posed the aye-aye to be a frugivorous animal, and it 

 must be confessed that the form of its molar teeth do 

 not indicate an adaptation to an exclusively insect diet. 



IX. GALEOPITHECID>. 



Notwithstanding the singular characters presented 

 by the animals forming this family, the last that we 

 shall refer to the order Quadrumana, their position in 

 the system is by no means so puzzling as that of the 

 Cheiromys ; in fact there can hardly be a doubt that 

 they form a connecting link between the two contiguous 

 orders of the Quadrumana and Cheiroptera, so that the 

 only question is whether we shall place them with one 

 or other of these orders, or, as has been done by Pro- 



