240 LEMURS. 



animal is known to the natives of the above-mentioned islands by the name of the 

 Malrnag. The same writer also informs us that only one young is produced at a 

 birth ; and that when the natives capture one of a pair, they are sure of securing 

 its fellow. When feeding, the tarsier sits up on its hind-quarters and holds its 

 food in its hands, somewhat after the fashion of a squirrel. 



THE AYE- AYE (Chiromys madagascariensis). 



The last of the lemur-like animals, and, at the same time, of the whole order 

 of Primates, is the aye-aye of Madagascar, which has teeth so utterly different 

 from all other members of the order that it was long considered to belong to the 

 Rodent order (rats, rabbits, etc.). 



The most peculiar feature about the teeth of the fully adult aye-aye is that the 

 front, or incisor teeth, are reduced to a single pair in each jaw, which are curved, and 

 have their extremities brought to a sharp chisel-like edge, admirably adapted for 

 gnawing and rasping hard substances. The structure of these teeth is in fact precisely 

 the same as in the front teeth of rats and beavers ; their sharp cutting-edge being 

 produced by the circumstance that while the body of the tooth is formed of the 

 comparatively soft ivory, the front surface is faced with a layer of hard flinty enamel. 

 And it will be obvious that the result of wear in a tooth of this type will be to produce 

 a chisel-like edge. It will further be apparent that such a tooth, if continually 

 employed in rasping away hard substances, would be very quickly worn away 

 altogether, if it were of the same length as ordinary teeth, and not provided with 

 some kind of renewal. This difficulty is obviated by the front teeth of the aye-aye 

 remaining open at their lower ends, and undergoing a continual process of growth ; 

 so that as their summits are worn away they are pushed further up from below. 

 In all these points their teeth are precisely similar to those of the Rodent Mammals. 

 A further resemblance to Rodents is shown by the absence of tusks in the aye-aye ; 

 and also by the cheek-teeth being separated by a long gap from the incisors, as 

 well as by being reduced in number, and having their crowns with nearly flat 

 surfaces, instead of being surmounted with the sharp cusps found in those of the 

 true lemur. Indeed, the total number of teeth in the adult aye-aye is only 

 eighteen; these being expressed by the formula i]-, eg, p^ } mf, or exactly the same 

 as in many Rodents. 



If, then, the teeth of the adult aye-aye are so exactly like those of a Rodent, 

 the reader may well ask why it is not placed among the rats and beavers, instead 

 of among the lemurs. To this it may be replied that in the young aye-aye the 

 milk- or baby-teeth are very much more like those of the true lemurs ; while the 

 anatomy of the skeleton and the soft parts is essentially that of a lemur, and not 

 that of a Rodent. The resemblance of the skull and teeth of the aye-aye to those 

 of a Rodent, is, indeed, an excellent instance of what zoologists term an adaptive 

 or parallel resemblance. When two animals belonging to totally different groups 

 have more or less nearly similar habits, it frequently results that they will closely 

 resemble one another in at least some part of their structure ; such particular 

 structure being the one best adapted for a particular mode of life. In all such 

 cases a superficial examination of the animals in question will frequently lead to 



