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 affinities 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, afforded 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 
