162 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



to that of the liver as this flows through the (■cecum. The lamella? are about thirteen in numoer. 

 The coecum opens into the intestine, not directly, but through a short neck of about the same 

 diameter as the intestine. The mouth of the coecum is surrounded by a muscular thickening of 

 the walls which is evidently a sphincter; ventrally the thickening extends from the opposite sides 

 toward the intestine as a V -.shaped ridge. From the opening of the neck of the coecum into the 

 intestine a thin, wide, projecting fold extends about 30 millimeters along the intestine toward the 

 anus. (Fig. 32, 1.) The fold is widest at the beginning, where it evidently forms a valve guarding 

 the coecum against the entrance of food from the intestine. As it passes along the intestine the 

 fold crosses over the ventral to the posterior side, at the same time becoming lower and lower 

 until it can scarcely be seen. The middle part of the fold is of considerable thickness and is 

 evidently glandular. From the point of the V formed by the sphincter of the coecum a low 

 ridge extends into the center of the pocket-like valve guarding the intestinal opening. From 

 the point of the V also a second fold (Fig. 32, 2) extends along the right side of the intestine nearly 

 parallel to the first fold. It is, however, not so prominent as the other. It gradually becomes 

 lower until it disappears. A number of oblique, apparently glandular, foldings of the ventral 

 side of the intestine connect the two folds. 



In some specimens, perhaps usually, a low, longitudinal ridge occupies the base of the channel 

 formed by the parallel folds. To this the oblique folds run and meet like the sides of a V, the 

 apex being directed toward the rectum. 



The first or posterior fold does not entirely disappear like the second, but is continued as a 

 low, scarcely perceptible ridge to the rectum. Close beside this, anteriorly we may term it, 

 another ridge runs exactly parallel for its entire length. (Fig. 32, 3, 3.) This third fold com- 

 mences near the end of the anterior fold of the first part of the intestine, but seems to have no 

 connection whatever with it. The two parallel folds commence upon the posterior side of the 

 intestine: as they run back along the second loop of the intestine they pass to the opposite side, 

 upon which they continue until the rectum is reached, when they become ventral and are lost 

 among the longitudinal foldings of this part of the intestine. As fchey make the sharp turn at the 

 back of the second loop the folds become much thickened; another thickening of the folds is 

 observable at the beginning of the second loop. Upon the. posterior side of the turn of the 

 second loop is a thick, foliaceous ridge 20 millimeters in length. (Fig. 32, -i.) This is connected 

 with the posterior of the two parallel ridges by a number of fine, transverse folds running across 

 the ventral side of the intestine. 



The intestine is extremely thin walled and plentifully supplied with blood vessels. In a 

 number of instances the diagonal ridges of the intestines were immediately above small arteries; 

 whether there is an intimate connection between ridges and blood vessels in all cases can be 

 determined only after an histological examination which my material did not permit. 



The structure of the cceeum seems to indicate that it may serve as a collecting place for the 

 secretions of the liver with which its own secretions are mixed. When the proper time arrives 

 the sphincter relaxes and the accumulated secretions are guided along the channel between the 

 parallel ridges of the intestine. As has already been described, the posterior and larger of the 

 two ridges of this part of the intestine serves as a valve to prevent food entering the coecum; 

 the disposition of the folds also renders it probable that the mixing of the food with the secretions 

 of the liver and coecum does not take place until some distance beyond the point where the 

 latter enter the intestine. There is no use in making any further conjectures as to the functions 

 of these ridges which, endostyle-like, extend along the intestine, until we know their histological 

 structure. 



The liver is a large, dark-brown, lobed mass which lies underneath the posterior part of the 

 crop and the stomach and cceeum, and surrounds parts of the intestine. (Fig. 27, L, L; L', L 1 .) 

 It is generally divided into five parts, two right and two left lobes, and a median portion which 

 may or may not assume the form of a lobe. The left lobes are very considerably larger than the 

 right. The main ducts of the right and left lobes unite in pairs, the ducts thus formed uniting 

 to make a common duct a short distance from the cceeum. The large ducts are covered by 

 small lobules, which empty their secretion directly into the ducts. The hepatic artery and its 



