1862.] PROF. OWEN ON THE AYE-AYE. 11 



intestines were wholly empty ; so that we cannot speak of its food 

 with positive certainty. The teeth are Pteropine in character, but not 

 so absolutely so as to preclude the possibility of this creature being 

 at least partially insectivorous, the molars showing a tendency to 

 mammillation on the external side of the longitudinal ridges into which 

 they are separated. The large folds in the interior of the stomach 

 seem to point to a vegetable diet. 



The sublingual fringed membrane is also an interesting peculiarity, 

 not only on account of its rarity, but because one of the few 

 other instances where it has been noticed is in an animal having no 

 one thing in common with the present, except that of living in the 

 same country. We sometimes see this happen ; an abnormal struc- 

 ture or peculiarity occurring in an animal restricted, to one country 

 will be found repeated in some other animal of that country no way 

 connected with or allied to it. 



This Bat was sent to me by my excellent friend, the Rev. Wm. C. 

 Thomson, one of the missionaries of the United Presbyterian Church 

 of Scotland, stationed at Old Calabar — a true Christian, an excellent 

 naturalist, and one whose devotion to the cause he has undertaken, 

 viz. the amelioration of the African negro, has been proved by the 

 greatest sacrifices from his youth upwards. 



Prof. Owen communicated the first part of his paper on the Aye- 

 aye {Chiromys madagascariensis, Cuv.), including an introductory 

 historical sketch of its discovery and the various opinions respecting 

 its nature and afl[inities set forth by naturalists from Buffon to the 

 present time. After commenting on the chief of these, the author 

 proceeded to narrate the circumstances under which the subject of 

 his descriptions, a nearly full-grown male, had been obtained from 

 Madagascar, and prepared for dissection, by the Hon. H. Sandwith, 

 M.D., C.B., whilst Colonial Secretary at the Mauritius. The habits 

 of the Aye-aye during the period in which it lived a captive at the 

 Mauritius with Dr. Sandwith, and also the habits of other individuals 

 that for a time were kept alive in the island of Reunion, by MM. 

 Lienard and Vinsor, in 1855, were next noticed. The specimen sub- 

 mitted to Prof. Owen, having been transmitted well preserved in 

 spirit, aiforded the means of a minute external description. The 

 extremities were described as follows: — "The fore leg turns freely 

 in the prone and supine position ; it is pentadactyle : the inner- 

 most digit stands out at an acute angle with the index, and is op- 

 posable to the other digits, making a prehensile hand, but in a 

 less perfect degeee than in the old-world or ' catarrhine ' quadru- 

 mana. The second, fourth, and fifth digits have the ordinary thick- 

 ness, — the fourth being almost twice the length of the second. The 

 third or middle finger is singularly attenuated, is rather shorter than 

 the fourth digit, and is terminated by a slender curved claw. It is 

 this seemingly atrophied digit which the Aye-aye inserts into the 

 burrows of the wood- boring caterpillars, after it has gnawed down to 

 and exposed them by its strong fore teeth, in order to extract the 



