Notes, iii. 14. . . 215 



rightly stated by A. {H. A. ii, 17, 27) to be without these cffica. In birds, as a rule, 

 there are two cceca at. the junction of small and large gut ; rarely, as in the heron, a 

 single ccecum. Sometimes, however, as A. notices here and elsewhere (^. A. ii. 17, 26),. 

 the coeca: are absent. T.his is the case for instance in the wryneck, woodpecker, lark, and 

 cormorant, among birds known to Aristotle. 



. 22. Meaning- of course the coecum and vermiform appendix. There is the greatest' 

 variety in the different mammalian orders as to the presence or absence of these. Cf. 

 Cuvier, Lefons, iii. 465. * 



23. Fishes, says A., do not digest their food well, because they have a short gut ; and 

 so they are ravenous. Similarly in the Timaus it is said that a long intestine was given 

 to animals to prevent insatiable gluttony. An abnormally short gyt is in fact a sufficient 

 cause for a ravenous appetite (cf. Schiff, Sur la Digestion, i. 44). The normally short gut 

 of a fish is, however, probably to be explained by the easy digestibility of their food. 

 Still there are some grounds for believing that the length of a fish's gut is not so great as 

 it might be with advantage. For if we compare one class of vertebrates with another, and 

 in so doing confine our attention to such species as live on similar food, e.g. the carnivorous 

 kinds, we find that the length of the gut in proportion to that of the body is less in fishes 

 than in batrachians or reptiles ; less again in these than in birds, and in birds than in 

 mammals. There is thus a gradual increase in the length of the gut, independently of 



'the character of the food, as we. get higher in the animal scale (cf. M. Edwards, Le(ons, 

 vi. 3S6).. 



24. What he stated before was that they had a single stomach, not a small one. The 

 single stomach is, however, small as compared with th? multiple stomach of the ruminants. 



25. The stomach of the. dog, as of Carnivora generally, is of small size, somewhat 

 elongated, and perfectly smooth within. That of the pig is of larger dimensions owing to 

 the very ample cardiac, cul-de-sac, is of globular shape, and presents on its internal surface 

 two transverse folds on either side of the cardia. Cf. H. An. iii. 17, 13, 



26. As a rule the intestine of mammalia is divisible into two parts, a smaH gut following 

 the stomach, and 'a. large gut succeeding to this. But in thosfe that are without a ccecum 

 there is no such distinction of size, the whole intestine being of nearly uniform diameter,. 

 or occasionally even becoming somewhat narrower as it advances towards the anus 



( Cuvier, Lemons, iii. 467), Though the dog is not one of these animals without a coecum, • 

 yrt its large intestine is exceptionally of scarcely larger calibre than its small gut {ibid. p. 

 485). The straining efforts of a dog in defecation are however scarcely attributable to this. 

 They are more pVobably due to the hard and earthy character of the fseces. 



27. The intestines, longer in Herbivora generally than in Carnivora, attain the greatest 

 length in ruminants. In the sheep, for instance, they are 28 times as long as the body ; 

 in the equally herbivorous but non-ruminating rabbit ten times ; in the carnivorous dog 

 only five times. 



28. " Few homed animals are small and none very small," says A. \H. A. ii. 17, 15 ; 

 but cf. iii. 2, Note 17^. Having a complex-stomach, their digestion, A. supposes, is more 

 thorough, and the material for, growth consequently more abundant ; and thus they grow 

 to large size. But this is scarcely in accordance with his former statement, namely, 

 that the complexity of the digestive apparatus is merely an atonement for their imperfect 

 mastication, and for the comparatively indigestible character of their food. 



29. Referring to the spiral coil of the colon, which- forms one of the characteris'tics of 

 the Artiodactyla (cf. Owen. VA-t. iii. 474). ' The colon becomes nalrower where it assumes 

 this spiral disposition. Later on A. calls this part the coil or helix (eA.(|). The straight 

 terminal part is of course the rectum. . • 



