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II. On the Aye-aye (Chiromys, Cuvier; Chiromys madagascariensis, Desm.; Sciurus 
madagascariensis, Gmel., Sonnerat ; Lemur psilodactylus, Schreber, Shaw). By 
Professor Owen, F.R.S., F.Z.S., &e. 
Read January 14 and 28, 1862, 
[Pirates XIV.—XXVI.] 
§ 1. Historical Introduction. 
THIS mammal was discovered by Sonnerat, in the island of Madagascar, about the 
year 1780, and was first described and figured in the work by that traveller, entitled 
* Voyage aux Indes Orientales et a la Chine, depuis 1774 jusqu’en 1781,’ Paris, 2 vols. 
4to, 1782. 
In the second edition (8vo, 4 vols.) of this work, published in 1806, from which 
I quote, the description is given in vol. iv. p.121; and the engraving of the animal, 
copied into subsequent works treating of the Aye-aye, down to Ellis’s ‘ Madagascar,’ of 
1858', forms plate 99 of the quarto volume of 140 plates accompanying the 8vo text of 
Sonnerat. 
The stuffed skin which is the subject of the above engraving was presented by 
Sonnerat to Buffon’, and is now in the Museum of Zoology, in the Garden of Plants, 
Paris, where, until very recently, it was the unique representative in Europe of the 
singular animal in question 
Sonnerat commences his description by stating that, ‘‘ although the Aye-aye much 
resembles a Squirrel, yet it differs therefrom by some essential characters, being also 
allied to the Lemur and the Monkey*.” Describing the fore foot, Sonnerat specifies the 
long, slender, naked joints of the middle digit, ‘‘ which the animal,” he says, ‘‘ makes 
use of to draw out of holes in trees the worms which form its food*.”’ 
Sonnerat had both a male and female, which, on board ship, were fed on cooked 
rice, and lived only two months. He obtained them from the west coast of Mada- 
gascar, which he affirms to be the part of the island they inhabit. The natives of the 
east coast declared that his specimens were the first they had seen; and their cry of 
1 «Three Visits to Madagascar,’ by the Rey. William Ellis, 8vo, 1858, p. 144. 
2 «Jai examiné de prés la peau d’un de ces animaux que M. Sonnerat m’a donné pour le cabinet du Roi.” 
—Buffon, Hist. Nat. Suppl. tom. vil. 4to, 1789. 
* «Ce quadrupéde se rapproche beaucoup de PEcureuil ; cependant, comme on le verra, il en différe par des 
caractéres essenticls: il tient aussi du Maquis et du Singe”’ (op. cit. p. 122). M. de Blainville can scarcely 
have had this passage in memory when he wrote, ‘mais jamais Sonnerat n’a cherché ses rapports naturels avec 
@ autres animaux connus” (‘ Ostéographie,’ “ Mémoire sur l’Aye-aye,” 4to, 1840, p. 34). 
4 « Tes deux dernitres articulations du doigt du milieu sont longues, gréles, dénuées de poils: il s’en sert pour 
tirer des trous des arbres les vers qui sont sa nourriture”’ (2.). 
VOL. V.—PART II. F 
