136 



ANATOMY OF THE RABBIT 



the sac being completed medially by the mediastinal pleura. The 

 two last mentioned are broadly connected with the pulmonary 

 pleura through the pulmonary ligament. 



The peritoneal cavity, the largest of the serous spaces, com- 

 prises in a mammal a general portion, the abdominal cavity, and 

 its posterior extension into the pelvis — in the male also into the 

 sac of the testis or scrotum. The general relation of the cavity to 

 the abdominal organs is indicated diagrammatically in Fig. 20. 



Its lining membrane, the peritoneum, 

 is divisible into two principal por- 

 tions, the parietal peritoneum, lining 

 the abdominal wall, and the visceral 

 peritoneum, investing the visceral 

 organs. Of the latter, the kidneys 

 encroach only to a minor extent on 

 the serous lining, so that they are 

 covered by peritoneum only on their 

 ventral surfaces. The digestive tube, 

 on the other hand, is removed to such 

 an extent from the abdominal wall 

 that the peritoneum forms a complete 

 serous coat, and is connected with 

 the parietal peritoneum of the wall 

 through a thin transparent membrane, 

 the mesentery. The latter consists 

 relation of the testis to its invest- of two platcs of peritoncum, cnclosins: 



ments: ai, inguinal ring; ce, caput . 



epididymidis; cr, cremaster muscle; bctWCCn them a thin layer of COU- 

 dd, ductus deferens; g, guber- , . i i • •• 



naculum; mes, mesorchium; ptv and nCCtlVC tlSSUC, the lamma meseuteni 

 vtv, parietal and visceral layers of • r i • • r 



the tunica vaginalis propria; pv, propria, lor the transmission oi ncrvcs, 



cavity of the vaginal process; s, , , , , . , ■, , 



integument of the scrotum; sv. blOOO-VCSSelS, and lymph CaualS. 

 spermatic vessels; t, testis. a • j* ^ j • i- i j. 



As indicated m an earlier chapter, 

 the relations of the abdominal portion of the digestive tube are 

 greatly modified by its elongation and displacement from a median 

 position. Thus, while in the embryo the common mesentery 

 (Fig. 51) is recognizable as a continuous median vertical fold, in 

 the adult it follows the convolutions of the digestive tube, and is 

 therefore considered as comprising corresponding parts. In many 

 cases the relations of these are greatly complicated by secondary 



showing 



