LIVER OF MAMMALIA. 485 



is sometimes divided., and the right more commonly so, the clefts 

 affecting an oblique course. The most noteworthy modification 

 in the Rodent order is that presented by the liver of Capromys. 

 Five primary divisions or lobes are indicated by the usual cha- 

 racters ; but each of these undergoes a subdivision ' into almost 

 innumerable angular lobules, varying in size from 3 to 5 lines : 

 though closely in contact they are quite detached from each 

 other, being appended by their apices to the larger branches of 

 the vena portre and hepatic arteries and veins. Each of the 

 lobules is partially subdivided into still smaller ones, the whole 

 structure approximating to a complete natural unravelling of 

 this conglomerate gland to its component acini.' 1 The gall- 

 bladder was large ; its contents limpid and of a greyish green 

 colour. The genera Mus, Cricetus, Lemmus, Echimys, Erethizon, 

 Synetheres, as a rule, are without the gall-bladder. Cuvier did 

 not find it in Sciurus maximus and in a species of Pteromys : but 

 in that dissected by Hunter (Pt. volucella) it was present, as also 

 in Sciurus cinereus and the common Squirrel. The Porcupine 

 (Hystrix) has a small gall-bladder, and the common Jerboa 

 (Dipus sagitta) has one of the usual size: the Cape Jerboa 

 (Helamys) has it not. In all other Rodents the gall-bladder is 

 present. In the Guinea-pig ( Cavia porcellus} Hunter remarks, 

 that the common duct, on reaching the duodenum, ' makes a turn 

 and passes with the gut for more than one-third of an inch, where 

 it becomes larger, and then it enters the <mt. This looks as 



o * o 



if this duct must make a turn somewhere, as it did not do it at 

 the gall-bladder.' 2 The bile 111 Rodents is thin and transparent, 

 yellow or greenish. 



All Carnivora have a liver with a left, a cystic, and a right 

 lobe, the latter usually subdivided into two or three lobules : in 

 some the left and the cystic are of equal size ; in others the left is 

 the largest lobe. In the Lion the cystic lobe is deeply cleft by 

 the suspensory fissure and the part to the left of that has been 

 counted as a smaller left lobe : there is a larger one to the left 

 of this, and two small lobes to the right of the part of the cystic 

 lodo-in<r the o-all-bladder. In the Walrus the liver is divided into 



o o o 



seven lobes, each of which is more or less notched at the under- 

 surface. Comparing this liver with the more simple forms in 

 Carnivora, we recognise the homologue of the right lobe, here 



1 cxxx". p. 70. The preparation is No. 8108, in xx. vol. i. (1833), p. 238. It 

 appears to be a normal structure in the Houtias. being described in xn. tome iv. (1835) 

 p. 454 ; also by SAY in the Eodent called Isodon, which appears to be identical with 

 Capromys. CLV". (1826). 2 ccxxxn. vol. ii. p. 209. 



