5GO 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 o-land into the base of the spleen before its bifurcation. 



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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 

 Moiiotr ernes. 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 (Baihyergus), 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 



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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 Leporida 

 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. Q-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. CCXXXYI. vol. ii. p. 213. 3 cxxvm". pp. 143, 157. 



