SPLACHNUM. 



[ 601 ] 



SPLEEN. 



yellowish, approximated in pairs and to some 

 extent conglutinated, when dry reflexed and 

 appressed to the capsule, when moist erect 

 and incurved at the apex. Inflorescence 

 dioecious, rarely monoecious. Columella 

 ordinarily emerging, capitate. 



SPLACHNUM, Linn. A genus of 

 Splachnacese (Acrocarpous operculate Moss- 

 es), remarkable for the large apophysis, 

 often umbrella-shaped. /S. ampullaceum, 

 Linn., not uncommon on the dung of ani- 

 mals on bogs, is a very handsome moss, with 

 purple or red capsules. S. vasculosum (figs. 



Fig. 679. 



674-678) is less common, occurring only in 

 high mountain districts. 



SPLEEN. This organ appears to occur 

 exclusively in the Vertebrata. The spleen 

 is covered externally by the peritoneum, ex- 

 cept at the hilus, where the vessels are con- 

 nected with it. 



Beneath the peritoneal tunic is a thin, 

 semitransparent, firm, fibrous coat, which at 

 the hilus accompanies the vessels, and forms 

 sheaths around them. 



The spleen is traversed by fibrous pro- 

 cesses, bands or trabeculse (fig. 679), which 



Fig. 680. 



Fig. 681. 



Fig. 679. Natural size. Portion from the middle of the spleen of an ox, washed ; showing the bands and their 

 arrangements. 



Fig. 680. Peculiar fibres from the pulp of the human spleen, belonging to the microscopic trabeculse. Magnified 

 350 diameters. 



Fig. 681. One of the same enclosed in a cell. Magnified 350 diameters. 



Fig. 682. Portion of a small artery from the spleen of a dog, with one of the branches covered with Malpighian bodies. 

 Magnified 10 diameters. 



Fig. 683. Malpighian corpuscle from the spleen of an ox. a, wall of the corpuscle ; b, contents ; e, wall of the artery 

 upon which it is situated ; d, its sheath. Magnified 150 diameters. 



