4,-)2 SCHULTE, SEI WHALE. 



remainder of the Spigelian lobe by a deep groove, which lodges the gastric artery; at this 

 point the reflection of the peritoneum of the lesser sac occurs, so that there is no proper Spigc- 

 lian recess and the surface of that lobe becomes adherent to the diaphragm. On the right 

 the processus papillaris is separated by a deep notch from the small depressed caudate lobe and 

 here the upper lobe of the pancreas is adherent. On the right the Spigelian lobe is bounded by 

 a narrow caval fissure, the approximated walls of which conceal the postcava deep in the sub- 

 stance of the liver. The dorsal surface of the right lobe is marked by an oblique ridge, beginning 

 at a small pyramidal eminence beside the postcava, the rudimentary caval lobe, and terminat- 

 ing at the caudal pointed extremity of the organ. This ridge marks the right limit of the renal 

 impression. Rostrad of it is the large triangular non-peritoneal surface and above this the emi- 

 nence corresponding to the sinus pleurae and the pulmonary impression. The renal impression 

 is very large, concave and obliquely placed. It terminates just caudad of the caval eminence, 

 which is non-peritoneal and adherent to the adrenal. Mesal to the renal impression, near the 

 caudal margin, is a triangular area slightly concave, which is in apposition with coils of the 

 small intestine. Between this and the deeply depressed hilum, the liver is in contact with 

 the duodenum. The fissure for the umbilical veins is deep and broad. The two umbilical veins 

 unite about a centimeter before reaching the hilum. The portal vein enters the hilum at 

 the extreme right rostral angle, having the hepatic artery on the left and the bile duct on 

 its caudal aspect. In the hilum it enlarges, as Carte and MacAlister also found, and is con- 

 nected to the left by a very large branch with the common umbilical vein and the beginning of 

 the ductus venosus. Before entering the liver the portal vein, lying in a groove between the 

 upper and the duodenal portions of the pancreas, and directed ventrad, rostrad and to the right, 

 is closely applied and adherent to the left side and venter of the postcava. In this way the fora- 

 men of Winslow is occluded, and the separation of greater and lesser sacs is further increased 

 by the adherence of the superior lobe of the pancreas to the caudate lobe. This latter condi- 

 tion has the effect of replacing the right or transverse portion of the gastro-hepatic omentum 

 by an extensive surface of contact and adhesion in the region of the pylorus, and of substitut- 

 ing for the usual peritoneal contact of these organs, a firm adhesion to the visceral surface of 

 the liver. 



As has been said, the Spigelian lobe is adherent to the diaphragm as far caudad as the 

 groove of the gastric artery. In two regions, therefore, the adhesion of the liver to adjacent 

 structures has been increased at the expense of the lesser sac. Nor was I able to convince myself 

 that the lesser sac extended to the right side of the oesophagus, but here owing to the small size 

 of the object and the friability of the liver at this point, the material was inadequate to permit 

 a definite observation. In three specimens of Tursiops truncatus from the New York Aqua- 

 rium, with very different conformation of the organs concerned, essentially the same conditions 

 obtained in their peritoneal relations. The foramen of Winslow was obliterated; there was 

 an extensive adhesion between liver and pancreas; the Spigelian lobe was extensively adherent 

 to the diaphragm. Between its ventral extremity and the oesophagus however was a small 

 remnant of the lesser cavity, but this was wholly cut off from the remainder of the lesser sac. 

 It is apparent therefore that in both groups of the Cetacea similar processes have been at work 

 to modify the topography of the upper abdomen, and that these have resulted primarily in a 

 closer approximation and more intricate coaptation of the several viscera to one another, so that 

 they have been welded into a complex with increased surfaces of adhesion, both to one another 

 and to the diaphragm. 



