582 CLASS XVII. 



carnivores on the contrary it is usually short; in the lion the pro- 

 portion stated ahove is as 3 : 1 ; the intestinal canal seems to be still 

 shorter in some insectivorous mammals. In the hyena the propor- 

 tion is as 8 : 1, and in the PIioccb the intestinal canal is still longer. 

 In man the above proportion is usually stated as 6 : 1\ But dif- 

 ferent individuals of the same species vary in this respect. At dif- 

 ferent periods of life also the proportion differs. In the foetus at the 

 earliest period the relative length is very small; at the last period 

 of foetal life and in early childhood on the contrary it is larger than 

 in the adult period of life'^. But not the length solely of the intes- 

 tinal canal, but the circumference also, the valves, the folds, the 

 villi more or less numerous are to be estimated; these all multiply 

 the absorbent surface, and thus a shorter canal may be equal in this 

 respect to a longer. In the seals and the hyena the intestinal canal 

 is narrow, and thus the relative length which is so remarkable is 

 reduced to correspondence with the animal food of which they 

 make use 3. 



The liver is situated below the diaphragm, chiefly on the right 

 side, as in man; but the greater the number of its divisions the 

 more does it extend to the left side. On the whole the liver is 

 more divided into lobes in the carnivorous animals than in the 

 vegetable feeders ; it is small on the contrary and little divided, 

 especially iu mammals with divided or compound stomach^. The 

 gall-bladder is wanting in a greater number of species of this 

 class than in any of the other classes of vertebrate animals; it 

 is not present in the carnivorous Cetacea, in the rhinoceros, ele- 

 phant, tapir, the horse, the sloth, the hamster and some other 

 rodents, and, amongst the ruminants, in the camels, lamas and 



^ The second edition of CuviERief. d'Anat. conip. IV. 2, 1835, pp. 182 — 195, edited 

 by DuvERNOT, contains copious tables. In Phoca vituUna, where this proportion is 

 differently stated, I found it as i : 18 or i : 19, 



® Compare Meckel in his Archivf, die Physiol. 1817, III. s. 61 — 65. 



^ On the digestive organs, besides the general works of Covier, Home, Meckel, 

 &c., the work of J. W. Neergaard, Commentatio anatomieo-physiologica sistens disqid- 

 sitionem an verum organorum digestioni inservientium discrimen inter animalia herbi- 

 vora, carnivora et omnivora reperiatur, Gottingae, 1804, 4to, may be consulted, in 

 which these parts are described in the horse, ox, hog and dog. 



^ The distinguishing of the different parts occurring in the liver by special names, 

 as was proposed by Duvernoy, we cannot detail here. See his Etudes sur le Foie ; 

 Ann. des So. nat. iv. 1835, Zool. pp. 257 — 269. 



