158 



Cestimony as to the native food of the Aye-aye. — The advantage to the forcihle action 

 of the jaw by the backward position of the condyle is recognizable, whether the fore 

 teeth of the jaw be fashioned for "biting," i.e. piercing as a dagger and becoming 

 infixed in a prey, or for " eroding " hard wood, as a gouge or chisel. 



Modifications of the mandible might be expected to be associated with the different 

 actions and applications of the fore teeth, aided or advantaged by the carrying back the 

 condyle and lengthening the lever of the biting powers. 



Prior to 1861 such backwardly placed as well as low-placed condyle was not known 

 in any real or alleged herbivorous or mixed-feeding animal. The anatomy of Chiromys 

 added, in that year, the interesting and instructive exception (admitting the Aye-aye to 

 be a mixed feeder). If it had been contended that the lower-placed condyle shown in 

 Plagiaulax, and dcducible in Thylacoleo, was absolute, independently of other characters 

 and considerations, in demonstrating the carnivorous nature of these marsupials, the dis- 

 covery of the structure of the mandible of the Aye-aye would have placed a seeming 

 objection and a feasible argument in the hands of an advocate of the non-carnivorous 

 character of Thylacoleo and Plagiaulax. If it were proved that the Aye-aye is a vege- 

 table feeder, not to say herbivorous, the same advantage would be his who had inter- 

 preted the fossil remains of Tliylacolco and Plagiaulax, notwithstanding the low-placed 

 condyle, as those of vegetarians, having their nearest affinities " to the marsupial her- 

 bivores, such as Halmaturus, Hypsiprymnus, and Phascolarctus " * . 



But the only testimony we have at present of the natural food of Chiromys shows it 

 to be " carnivorous " in the sense of subsisting on the flesh or insect-tissues of wood-boring 

 larvae ; all the peculiarities of its structure are physiologically or teleologically intelligible 

 only on this basis. Hunter, it is true, made his captive Sea-gull subsist wholly on 

 grain f, and induced a Kite to eat and thrive on bread alone J. 



Save for loyalty to truth in the abstract one might be willing to accept the evi- 

 dence adduced by Dr. Falconer § of the food given to captive Aye-ayes as proof of 

 its being naturally a vegetable feeder ; but I believe the position of the mandibular 

 condyles to be related to the powerful working of the pair of incisors. Such work is not 

 needed for dividing the stems of rice or the stalks of dates or bananas. Nor are the 

 Aye-aye's conditions of condyle present in Hypsiprymnus or in any other vegetable feeder. 

 No one can admit the Aye-aye to be a strict vegetarian who gives credit to the subjoined 

 testimony : — 



" It so happened that the thick sticks I now put into his cage were bored in all direc- 

 tions by a large and destructive grub, called here the Moutouk. Just at sunset the 

 Aye-aye crept from under his blanket, yawned, stretched, and betook himself to his tree, 

 where his movements are lively and graceful, though by no means so quick as those of 



* X. p. 352 ; XI. p. 435. 



t Home, ' Lectures on Comparative Anatomy,' 4to, vol. i. p. 271. Owen, • Catalogue of the Physiological 

 Series, Museum of the Royal College of Surgeons,' 2nd ed. 8vo, p. 151, prep. no. 523. 



% Hunter, 'Animal Economy,' Owen's Ed. 8vo, 1837, p. 112. § X. p. 364; XI. p. 449. 



