330 Prof. M^Tntosli's Notes on the Tunny. 



The oesophagus is very short and wide, with muscular walls, 

 and is deeply plicated longitudinally on the inner surface. 

 It is about 8 inches in diameter at the cardiac end of the 

 stomach. The surface near the latter is villous, but it is 

 distinguished from the surface of the stomach by the greater 

 number of rugie in the latter. 



Tlie stomach is a large conical sac measuring 25 inches in 

 length from the cardiac oritice to the apex posteriorly. Its 

 inner surface is complexly rugose from longitudinal and 

 transverse reticulations, and the contraction of the thick mus- 

 cular mass in spirit considerably intensities this feature. 

 Externally tlie superficial muscular layer is chiefly longitu- 

 dinal, then follows a series of circular fibres ; while internally 

 a layer apparently of interwoven fibres occurs, with much 

 connective tissue. The whole forms a powerful muscular 

 chamber, in which were three haddocks (11, 11, and 9 inches 

 respectively), two lemon-dabs (9j and 8j inches), and two 

 common- dabs (each 1^ inches). While searching for these at 

 the bottom of the water it had encountered the trawl-net. 

 The pyloric region of the organ is situated about 3 inches 

 from the cardiac opening and therefore near the oesophagus. 

 The walls of the diverticulum leading to the pyloric valve 

 are rugose and remarkably massive, especially at the termina- 

 tion, near which one large boss projects from the posterior 

 wall of the canal. These thick folds form a very efficient 

 valve, which arrests even small bones, such as the vertebrae 

 of the haddocks and dabs, and in all probability peristaltic 

 action sends them out of the mouth if bulky *, or they remain 

 there till the gastric secretion disintegrates them. 



At the cardiac end of the stomach were five examples of a 

 large Distomum^ apparently D. clavafmn, Rud., a species 

 which has been found in the stomach of Pelamys sarda and 

 in the intestine of Corypha'ua hippurus in the Mediterranean, 

 as well as in the present form f- Amongst the mucus of the 

 same organ were a large Ascaris (imperfect), two Echino- 

 rhynchi^ probably from the haddocks or other prey, and a 

 fragment of a mollusk from the same source. 



The calibre of the duodenum at its commencement is com- 

 paratively small, and externally the distinction between the 

 two regions is well marked on palpation. Beyond the promi- 

 nent boss at the pyloric valve are a few longitudinal and 

 oblique ridges of the canal ; but these soon cease, and the 

 proper duodenal region of the gut is smooth, witli the excep- 



* A common occurrence in Hslies. 



t Carus, ' Prodromus Faun. Mediter.' i. p. 131. 



