382 CETACEA. 



stitutes a compact layer a quarter of an inch thick all round the sides of the gland, 

 except at the union with, the button-shaped splenule, and invests the internal 

 portion which has the characteristic texture of the spleen. 



Liver (PI. XXVII, figs. 12 and 13). — In one old female, this organ, after 

 thorough preserA^ation in alcohol, measured about 12 inches in transverse and 9 inches 

 in longitudinal or antero-posterior diameter. As in most of the whale tribe, it is 

 thick, smooth, and free from lobular divisions. The umbilical cleft is, however, 

 deepish, defining almost equal-sized dextral and sinistral moieties. A short shallow 

 sulcus or merely superficial indentation on the posterior aspect of the left side was 

 present in this sj)ecimen. The vena cava (v.c.) runs along the posterior border. 

 The hepatic vessels (A.) enter about the middle of the gland, and they exhibit thick 

 dense fibrous walls sui-rounded by what appears as subsidiary vascular tissue, a 

 partial rete mirabUe. 



Ductus communis clioledochus. — The liver opens by two orifices into this duct 

 (Plate XXVII, fig. 9), and the pancreas by a similar number placed immediately 

 below the openings of the bile canals. One of the hepatic ducts from the left lobe 

 is situated anterior to that from the right, which is double, immediately before it 

 enters the common duct. The duct is a great wide canal three-fourths of an inch 

 in diameter, almost equalling the capacity of some portions of the small intestine 

 when laid open, but it gradually diminishes in its course of five inches to the 

 duodenum to a capacity of 0-06 inch at its opening into the intestinal canal. At its 

 commencement, marked folds pass down from the orifices of the bile ducts, trans- 

 verse to the long axis of the tube, but beyond the pancreatic ducts there is a limited 

 area in which the folds are oblique. Throughout the rest of the duct the mucous 

 membrane is thrown into strong wavy transverse folds, and at about its latter half 

 these are traversed by three or four longitudinal furrows. To the naked eye the 

 mucous surface is seen to be minutely pitted and transversely grooved, and in some 

 parts this structure recalls the appearance presented by the mucous membrane of the 

 gravid uterus of this species. When examined with a hand lens the pits are seen 

 to be separated from each other by finely membranous septa and the grooves to be 

 divided into compartments by similar septa. The pits and septa are of most frequent 

 occurrence in the hollows between and crossing the transverse folds, but they occa- 

 sionally occur on the folds themselves. 



A microscopical examination of the walls of this common bile duct (PL XXXVI 

 fig. 16) disclosed a delicate layer of short columnar epithelium coverino- the free 

 villous-like surface. Into this opened the mouths of many long branchino- lobular 

 glands (</,), these latter being crammed with large nucleated cells. These glands, 

 therefore, doubtless furnish a mucous or other secretion to be added to the bihary 

 and pancreatic fluids. Beneath them, is a thick layer of elastic areolar tissue (c), 

 and agam, considerable strata of transverse and oblique, nucleated and unstriped 

 muscular fibres (to.). 



Intestmes.—l shall limit my remarks regarding the intestines to pointing out 

 that the mucous folds of the duodenum do not form marked valvute conniventes as 



