560 ANATOMY OF VERTEBRATES. 



In the Ornithorhynchus, the spleen, fig. 308, u, u, is relatively 

 large, and consists of two lobes bent upon each other at an acute 

 angle : the anterior and right lobe is four inches long, the posterior 

 and left lobe two inches and a half; the right lobe is bent upon 

 itself. The artery of the pancreas is continued from the left end 

 of that gland into the base of the spleen before its bifurcation. 

 In the Echidna, besides the two lobes which are continued for- 

 wards from the left side, there is a third shorter descending 

 appendage. The lobes are thin and moderately broad in both 

 Monotremes. The Marsupialia repeat the bent or bilobed cha- 

 racter of the spleen as shown in that appended to the left end of 

 the stomach of the Phascogale, fig. 309. In the great Kangaroo 

 (Macropus major) I found the main body of the spleen ten inches 

 long, and the rectangular process six inches ; both parts were 

 narrow and thin. 



In Lissencephala the spleen presents a more simple form, 

 oblong, flattened, fig. 323, / (Rhynchocyon), with one end in 

 contact, and having the usual vascular relation with the pan- 

 creas, ib. p. The spleen is relatively longer and narrower in the 

 Mole and Hedgehog : it is a thin elongate body, loosely sus- 

 pended, in the Squirrel, where it lies to the left of the epiploon, 

 as in the Marmot: it follows, similarly suspended, the great 

 curve of the stomach in the Mole-rat {Bathyergus), being thickest 

 at the left and upper end : in the common Rat the spleen has an 

 oblong triangular form : in the Vole it is broader at the lower 

 than at the upper end : in Capromys it has an elongate trihedral 

 form, broadest at the lower end: in Lagostomus the spleen is 

 triangular, with the upper and anterior angle most produced. 1 It 

 varies from the round to the oblong shape in the Porcupines and 

 Agoutis, and occasionally a small detached spleen is added, in 

 the epiploic suspending duplicature. Hunter notes, in the Capy- 

 bara, the close resemblance of the spleen in shape to that of Man; 2 

 and it is less elongate than usual in the Guinea-pig. In Leporidce 

 it resumes its narrow elongated figure. In Dasypus Peba the 

 spleen is elongate and three-sided ; I found it 2 J inches in length ; 

 in contact with the pancreas : in Das. 6-cinctus the spleen is 

 broader and flatter, and there was a small supplemental spleen in 

 my subject. 3 In the three-toed Sloth the spleen is an inch in 

 length, oblong, thickest at the lower end, suspended in the 

 epiploon : in the two-toed Sloth it is almost round, flat, and thin, 

 and closely attached to the second compartment of the stomach, 



1 ccxn". p. 176. 2 ccxxxvi. vol. ii. p. 213. 3 exxvm". pp. 143, l.j". 



