156 



form of a slit with tumid margins situated on the middle of the ridge 

 which separates the two pouches, and therefore liable to be closed by 

 the lateral pressure of the faecal matter distending those pouches. 



" Should this structure be confirmed by subsequent examinations 

 of other individuals of the six-banded species, the absence of a ccecum 

 can no longer be admitted among the generic characteristics of Dasy- 

 pus. And it is interesting to observe, that the absence or presence 

 of a ccecum as a generic distinction holds with as little force in the 

 allied genus Myrmecophaga : for according to Daubenton there exist 

 in one species {Myrm. didactyla, Linn.) two small cceca; while the 

 Tamandua (Myrm. Tamandua, Cuv.), we are assured by M. Cuvier, 

 has not any. In these apparently capricious variations of structure 

 among the Edentata, it is impossible not to observe a tendency or an 

 approximation to the structure of another class; which I am inclined 

 to think is that of Birds. For in addition to the double ccecum, a 

 peculiarity so remarkable in that class, we have also a gizzard-like 

 structure exhibited in the tendinous external appearance and thickened 

 muscular coat of the stomachs of the Dasypodce, and a still nearer 

 approximation to that form of stomach in the Manis, where the muscular 

 coat at the pyloric end is 5 lines in thickness, and the inner surface is 

 defended by a strong cuticle, roughened with papillce . A similar struc- 

 ture exists also in the Myrmecophagce , which moreover supply the want 

 of grinders in the mouth by swallowing, in the same manner as the 

 Gallinaceous Birds, small pebbles for the purpose of bruising and de- 

 stroying the vitality of the insects which constitute their food. [See 

 Burt in Asiatic Researches, vol. ii. p. 354?, with respect to the fact of 

 small stones and gravel being swallowed j and Lawrence's Blumen- 

 bach, Comp. Anat. 2nd edit. p. 89. for the true physiology of the fact.] 

 In this genus also we find mucous glands about the os hyoides of the 

 nature of those follicles which in Birds take the place of the conglo- 

 merate salivary glands of the Mammalia, and the secretion of which 

 serves in the Ant-eaters, as in the Woodpeckers, to lubricate a pro- 

 jectile tongue. In another group of the Edentata, viz. the Bradypoda, 

 we are presented with a still more marked affinity to the structure of 

 birds, in the abnormal number of cervical vertebra: exhibited in the 

 three-toed Sloth, a peculiarity which it is difficult to refer to any other 

 circumstance than the disposition of nature to pass by means of this 

 anomalous order from the Mammalia to the Birds. The transition is 

 indeed nearly completed by the Monotremata ; for of the two genera 

 contained in this order, Echidna presents us with the quills, and 

 Ornithorhynchus with the beak, of a bird ; and it is far from being 

 proved that the mode of generation is not the same. 



" With respect to the Armadillo: The commencement of the colon, 

 which is formed by the union of the two cceca above described, is 

 nearly 2 inches in diameter, but quickly diminishes to half an inch : 

 near its termination it is again slightly dilated. A well marked chain 

 of lacteal glands accompanies the mesenteric artery. 



" The lungs were divided into three lobes on both sides, the addi- 

 tional lobe having reference probably to the greater breadth of the 

 chest in this species. The larynx, pharynx, fauces and tongue pre- 



