332 Prof. M'Intosh's Notes on the Tunny. 



ridges, which frequently run together, the intermediate surface 

 being minutely reticulated. The ridges and reticulations keep 

 the character just noted till within 4 inches of the gut, where 

 the wall becomes denser, ])artly from the great development of 

 the longitudinal ridges, which resemble folds like those of the 

 " manyplies," so that only fluid will readily pass along. 

 Under a lens the surface is still reticulated, but more minutely. 

 These rugaj continue, in the forward course of the canal, 

 through the wall of the gut to its termination in the pit. 

 Thus the differences between the lining membrane of the 

 gall-bladder, its duct, and the cystic appendix are marked, 

 though the minute black specks are everywhere present. 



Into the duodenum, which has about the same calibre as 

 the rest of tlie gut, seven (Cuvier and Valenciennes say five *) 

 large ducts enter from the great glandular pyloric mass, 

 the casca of which are about a line and a half in diameter. 

 The first of these (having a diameter of half an inch) joins 

 the canal about an inch from the pylorus ; it consists of a 

 main stem an inch in length, which splits dichotoniously into 

 a number of branches, each of which resolves itself into a 

 carrier for a bundle of the ultimate casca, fat, and connective 

 tissue, forming a terminal process of about 3 inches in length. 

 The second main duct enters the duodenum close to the fore- 

 going, and it has a similar diameter, though the stem reaches 

 the length of 3 inches. The chief branches are also much 

 longer, so that the terminal casca extend outwards about a 

 foot from the gut, and thus permit a ready disposition of the 

 parts in the abdomen. Further, the smaller branches are for 

 the most part disposed on one side of the larger, so as to give a 

 fan-like arrangement when they are stretched on a flat surface. 

 The third is a short trunk (placed about half an inch from the 

 second), which quickly divides into a large number of branches 

 to the cffica, which thus approach the gut proximally (within 

 1\ inch), but are nearly 3 inches distant terminally. The 

 fourth duct is fully f inch in diameter, and enters the duo- 

 denum about If inch further backward. After a short course 

 of f inch it breaks up into a number of branches, which 

 chiefly spring from the anterior region. The fifth is an inch 

 behind the preceding, and consists of a short wide tube (1 inch 

 in diameter), which splits into a fan -like series of branches, 

 the cffica being near the gut. The sixth (1 inch distant from 

 the fifth) and the seventh (1^ inch behind the sixth) have 

 similar short trunks with a fan-like distribution of their 

 branches, the ultimate cseca in the latter being considerably 

 shorter than in front. 



* Op. fit. vol. viii. p. 05. 



