168 BR. C. F. SONNTAG OK THE 



of pigment. These granules may, however, have a pathological 

 significance. 



The Spleen. 



The spleen, as Rapp pointed out (10), lies on the right side of 

 the pylorus. It is, in my specimen, separated from the latter by 

 the splenic limb of the pancreas, with which it is surrounded by 

 the layers of the dorsal sheet of the great omentum (text- 

 fig. 11, B). Its total length is 7'7 cm., width of the oval part 

 1*3 cm., and thickness -75 cm. 



It consists of an oval posterior part, and a long narrow anterior 

 part which is twice bent on itself, but the latter has a small thick 

 concealed process. On the inner side there is a small circular 

 accessory spleen lying within the splenic limb of the pancreas. 



The right-sided position of both pancreas and spleen introduce 

 modifications in the peritoneum. In my specimen the conditions 

 induced by the former make the peritoneum different even to 

 that of forms of B. tridactylus in which the spleen and pancreas 

 lie as described by other authors. 



The position of the spleen offers a problem for the embryologist. 



The Peritoneum. 



The Great Omentum (Plate II. A, f). 



The great omentum is attached to the right side of the ventral 

 limb of the pylorus, but nowhere is it fixed to the greater cur- 

 vature of the stomach. It has dorsal and ventral sheets, each 

 composed of two fused layers. 



The ventral sheet (text-fig. 12, A, vs) is attached to the right 

 border of the whole of the ventral limb of the pylorus, and the 

 right border of the first part of the duodenum. It separates 

 into two layers which surround these structures. The ventral 

 layer is continued from the pylorus on to the ventral surface of 

 the cardiac stomach, and the dorsal layer passes from the ventral 

 to the dorsal part of the pylorus, thereby forming the left wall of 

 the lesser sac. On the dorsal limb of the pylorus it meets with 

 the dorsal sheet of the great omentum which has returned from 

 the pancreas and spleen. 



At the convexity of the pylorus the ventral and dorsal sheets 

 meet, thereby closing the lesser sac posteriorly, and the ventral 

 sheet fuses anteriorly with the mesoduodenum (clotted line in 

 text-fig. 14, A). 



The dorsal sheet (text-fig. 12, A, ds) passes dorsally and to the 

 right from the free edge of the omentum and, at the ventral 

 border of the pancreas, it splits into right and left layers. The 

 former passes round on to the right surface of the splenic limb of 

 the pancreas, and is carried off round the spleen which it com- 

 pletely encloses ; returning to the pancreas again it covers the 

 right surface. The left layer covers the left surface of the 

 pancreas and, at the dorsal border, the two layers come together 



