102 FOSSIL MAMMALIA OF THE 



But were the maximised cbisel-teetli, with a low-placed mandibular condyle and 

 biting power of jaw, needed to divide the stems of rice or the stalks of dates or of 

 bananas ? 



SoNNERAT, besides specifying the compulsory food on which his captive Aye-aye 

 perished, describes the long, slender, naked, middle digit, and states : " II s'en sert pour 

 tirer des trous des arbres les vers qui sont sa nourriture," ^ I understand this to mean that 

 larvae (' vers ') are its natural or staple food. The affirmation may have been made from 

 Sonnerat's observations on Cheiromys in a state of nature, or on the reports of natives 

 of Madagascar, or on both authorities. 



Dr. Sandwith adds to his account of the substances on which he fed his Aye-aye a 

 detailed statement of observations of its power of detecting, exposing, and extracting the 

 xylophagous larvae, which it eagerly devoured, confirmatory in an important and instructive 

 degree of Sonnerat's statement of its food in a state of nature :' nor is other testimony to 

 the same fact wanting.^ And to the acquisition of such animal food the dental and 

 mandibular machinery of Cheiromys are as perfectly adapted as was the same machinery 

 in Plagiaulax to the different kinds of animal food which that extinct Marsupial 

 captured and fed upon. 



The large front teeth in Cheiromys are curved in segments of circles (fig. 19,2), the 

 depth of the tooth exceeding the breadth ; the working surface is elongated, in breadth 

 equalling that of the base of the tooth, with a front convex enamelled border, forming the 

 apex of the gouging tool. 



With what molars are these scalpriform teeth associated ? Few, small, tubercular 

 (fig. 19, ni) : fitted for squeezing the soft animal nutriment out of the tegumentary 

 covering of a caterpillar ; not adapted for trituratory mastication of such vegetable food as 

 calls for the more complex and massive molars of the Kangaroos, Potoroos, and Koalas, 

 or of the xylophagous Voles and Beavers. 



In another part of the polemical paper advocating the macropodal affinities of 

 Plagiaulax, the angular process of the jaw as a salient apophysis is stated to be wanting 

 in that genus, and an argument for its herbivority is based upon the assertion that " this 

 process is a very constant character of the carnivorous jaw,'' and that " it is well developed 

 in the minute insectivorous Myrtnecobius."^ 



To this I reply, that the angular process is not present in Stenorhynchus and some 



The species oi Hypsiprymnus are strictly vegetable-feeders." Falconer, ' Quarterly Journal of the Geological 

 Society,' vol. xviii (1862), p. 364 ; ' Palseontological Memoirs,' 8vo, 1868, vol. ii, p. 449. " Dr. Sandwith 

 fed his captive Aye-aye upon bananas and dates." lb., ib., p. 450. By parity of reasoning the Kite (Home, 

 "Lectures on Comp. Anat.," 4to, vol. i, p. 271) and Sea-gull (Owen, "Physiol. Catalogue of Mus. Coll. 

 Surgeons," 2nd ed., Svo, p. 151) might be cited as herbivorous. This and the passage on the rice-feeding 

 were read to the Zool. Soc, Jan. 14th, 1862. 



' "Voyage aux Indes Orientales," &c., Paris, 4to, 1782, and Ed. 8vo, 1806, vol. iv, p. 122. 



2 Owen, "On the Aye-aye," 4to, 1863, p. 25. 



3 Falconek, ' Quart. Journ. Geol. Soc.,' vol. xviii, p. 363 ; ' Palseont. Memoirs,' p. 448. 



