CETACEA. 



575 



rumination can take place. The first cavity 

 is continued in the same line with the oesopha- 

 gus, having the same structure, and not being 

 divided from it by any sensible constriction ; 

 its commencement is indicated by the orifice 

 leading into the second stomach, beyond which 

 orifice it is continued in the form of a dilated 

 ovate cavity (a). It is lined with a cuticle, 

 and its inner surface is beset with small rugae. 

 A number of large irregular projections sur- 

 round the aperture leading to the second ca- 

 vity, and are calculated to prevent the passage 

 into the second of any substances save such 

 as are of very small size. Notwithstanding 

 the nature of the lining membrane the di- 

 gestive processes are considerably advanced 

 in this cavity, which does not act simply as a 

 reservoir. It is probable that the secretion of 

 the second stomach, which is highly glandular, 

 regurgitates into the first and assists in pro- 

 ducing the dissolution of the carneous parts 

 of the fishes, the remains of which are 

 usually found in it. The thick cuticular 

 lining terminates abruptly at the small ori- 

 fice leading into the second stomach (b). 

 The interior of this cavity presents a series of 

 close-set thick longitudinal wavy rugae, laterally 

 indented into one another. The internal layer 

 is thick and of a peculiar structure : according 

 to Sir David Brewster, " it seems, in its wet 

 state, to consist of tubes or fibres perpendicu- 

 lar to the two membranes which inclose them, 

 and the upper surface of one of the membranes 

 is covered with hollows or depressions corres- 

 ponding with the extremities of the tubes or 

 fibres. A more minute examination, conducted 

 in a different way, proves these perpendicular 

 portions to be tubes. In order to dry it, 1 

 pressed it between folds of paper, and the effect 

 of the compression was to press together nearly 

 all the tubes, and make the whole one dense 

 mass, of a dark brown colour; but when it be- 

 came dry and slightly indurated, I drew it 

 out as if it had been India-rubber, and the 

 tubes opened, and the mass became white." 



The membrane next the cavity of the sto- 

 mach is perfectly smooth ; the one external 

 to the fibres is a vascular and cellular tunic, 

 and is inverted by the layer of muscular fibres 

 continued from the preceding cavity. The 

 communication with the third stomach is near 

 the lower end of this cavity. The third com- 

 partment is a small round vascular cavity, into 

 which the second opens obliquely : it is lined 

 by a smooth and simple villous tunic. It is 

 not visible exteriorly, and does not exceed an 

 inch in length in the Porpesse, but in the 

 Hyperoodon is about five inches long. The 

 fourth cavity (c, c) is long and narrow, and 

 passes in a serpentine course almost like an 

 intestine; the internal surface is smooth and 

 even, but villous. It opens on the right side 

 into the duodenum (d}, which is much dilated, 

 and, as in the human subject, is without valvulae 

 conniventes at its commencement. The pylo- 

 rus is a smaller opening than that between the 

 third and fourth cavities.] 



Some authors speak affirmatively of a con- 

 siderable bladder, which in the Rorquals, after 



death, comes up into the mouth and forces the 

 two jaws asunder. Now what is the nature of 

 this vesicular mass, of which other authors say 

 nothing ? To what organic system does it be- 

 long ? This has never been made a subject of 

 enquiry. It has been considered as belonging 

 to the respiratory system, or as an air-bladder 

 analogous to that offish. Is it not more proba- 

 bly a portion of the stomach distended by the 

 gases formed there ? 



In general the Spouting Whales have no 

 ccecum. However, a trace of this gut has 

 been found in an oval elevation in the Plata- 

 nist ; a ccecum exists also in the Piked Whale 

 and in the Whale-bone Whale. The variations 

 in form or affinity of the spleen and the liver 

 appear to have no essential relation with the 

 forms of the stomach. 



[Mr. Hunter observes that " there is a con- 

 siderable degree of uniformity in the liver in 

 this tribe of animals. In shape it nearly re- 

 sembles the human, but is not so thick at its 

 base nor so sharp at the lower edge, and is 

 probably not so firm in its texture. The right 

 lobe (e, Jig. 263) is the largest and thickest, 

 its falciform ligament broad, and there is a 

 large fissure (g) between the two lobes, in which 

 the round ligament passes. The liver towards 

 the left (f) is very much attached to the sto- 

 mach, the little epiploon being a thick sub- 

 stance. There is no gall-bladder." " The 

 pancreas is a very long, flat body, having- its 

 left end attached to the right side of the first 

 cavity of the stomach : it passes across the 

 spine at the root of the mesentery, and near to 

 the pylorus joins the hollow curve of the 

 duodenum, along which it is continued, and 

 adheres to the intestine, its duct entering that 

 of the liver near the termination of the gut." 

 Phil. Trans. 1787, p. 410. 



The structure of the biliary organs has a 

 closer resemblance to that of Quadrupeds 

 in the Herbivorous Cetacea, and differs from 

 that above described in the presence of a gall- 

 bladder, besides some minor points. 



In the Dugong the liver is a transversely- 

 oblong viscus, divided into three lobes with a 

 fourth small process at the root of the left lobe, 

 representing the lobulus Spigelii. It is as 

 usual convex towards the diaphragm, but rather 

 flattened than concave towards the viscera, the 

 anterior margin thick and rounded. Of the 

 three larger lobes the middle one is the smallest, 

 of a square shape, projecting forward, and as 

 it were overhanging the gall-bladder, which 

 is lodged in the middle of the inferior surface. 

 The ligamentum suspensorium is continued 

 upon the middle lobe, immediately above the 

 gall-bladder, the anterior margin of this lobe 

 being notched to receive it, and the remains of 

 the umbilical vein entering the liver an inch 

 above the fundus of the gall-bladder. The 

 two lateral lobes are more than double the size 

 of the cystic lobe, and of these the left is the 

 largest. Both these lobes are concave to- 

 wards the small middle lobe, which they 

 thus surround and conceal. The lobulus 

 Spigelii is of a flattened and square shape, 

 measuring one inch and a quarter in length 



