630 LARUS ARGENTATUS, HERRING GULL. 



emootli, except jnst at its termination, where the mucous membrane is prolonged into 

 long, acute papilla', ; aud from this, as a centre, extends on cither side a triantfular bed 

 of large, acute, reversed papilhe, stretching quite to the borders of the laryngeal 

 elevation. 



The oesophagus is, as in all the family, very capacious, and capable of great distension. 

 In its undilated state its mucous membrane is thrown up into exceedingly prominent 

 longitudinal stria;, nearly all of which run the whole length of the tube. The muscu- 

 lar layers, both circular and longitudinal, are also extremely thick and powerful. 

 The o?sophagus itself is quite straight and of pretty uniform calibre. At the proven- 

 tricnlus it dilates a little, and at the same time bulges a little to the left. The gizzard, 

 also, is not in a direct line with the oesophagus, but its greatest convexity inclines con- 

 siderably to the right. 



Just at the proventri cuius the straight longitudinal oesophageal folds become convo- 

 luted (in the undilated state of the organ), and then gradually lose themselves in the 

 irregular eminences of the soft, very vascular, proveutricular mucous membrane. This 

 portion of the tube is, when contracted, divided into six or eight large prominent folds, 

 divided by deep narrow sulci, corresponding to similar elevations and depressions in 

 the cuticular lining of the gigerium. The solvent glands form a perfect uninterrupted 

 zone, quite around the tube, which has a wt 11-defined and straight termination in the 

 ordinary oesophageal mucous membrane. The sensible differences of this portion of 

 the canal are the absence of longitudinal rug£e, the substitution for them of irregular 

 eminences and depressions, its grayer color, soft velvety feel, greater vascularity and 

 thickness, and the i)resence of minute puncta, which are scattered thickly over its en- 

 tire surface — the mouths of the solvent ^jjlands. In cutting into the walls of the pro- 

 ventriculus these glands may be seen with an ordinary lens, or even with the naked 

 eye, as simple follicles, with a somewhat bulging outline, proceeding straight from their 

 blind extremities to their opening in the mucous membrane. They lie sitle by side im- 

 bedded in the tissue of the walls of the proventriculus, and are of a length but little 

 less than the thickness of the parietes itself. 



The gigerium, in situ, is far back in the abdomen, its middle about opposite the last 

 rib and to the left side, lying nearly apposed to the abdominal parietes. It is in shape 

 a somewhat irregular and liattened ovoid ; its walls comparatively thicker and more 

 powerful than in the other subfamilies. The musculi laterales, at their thickest i>ortions, 

 measure a thirol of an inch or more in thickness. If we consider the gizzard as extend- 

 ing upward as far as the cuticular lining extends, i. e., to where the zone of gastric 

 glands begins, it is divisible into two portions : a lower, with strong, thick, mnscular 

 walls, and very convex outline; and an upper, narrower, more constincted portion, 

 with much thinner and less powerfully contractile parietes. The hard cuticle lines 

 both these portions nninterrnptedly, extending quite to the glandular zone. It pre- 

 sents the ordinary rugte and convolutious. 



The duodenal fold is rather short, scarcely two inches in length. After forming this 

 fold, the intestine proceeds in a pretty straight course to make a second fold, longer 

 than the first, and quite disconnected with it. After that the intestine forms a mass of 

 closely aggregated convolutions. Between six and seven inches from the ca^ca the in- 

 testine returns toward the duodenum, near the gizzard, and forms a definite fold, much 

 of the same character as, and closely api>osed to, the first duodenal fold, with which it 

 is connected for the greater part of its course. There are only slight convolutions be- 

 tween this last fold and the cceca, beyond which the intestine proceeds in a nearly 

 straight course to the cloaca. 



The intestines measure, from the pylorus to the anus, a little over forty inches. 

 There is but little difference in calibre throughout their length until we reach the cloaca; 

 the duodenum being, however, if anything, a little the largest. A little beyond the 

 ttrniinatiou of the duoderal fold, just four and a half inches from the pylorus, the he- 

 patic duct opens ; one inch further down the cystic duct is received by the intestine; 

 auol just half way between the two is the orifice of the pancreatic duct. These three 

 ducts, which convey the hepatic and pancreatic secretious into the intestine, opeu 

 nearly on a line with each other on the mesenteric edge of the iutestine. 



The ca'ca resemble those of Ster)ihia', and difter greatly from those of Lestridlna;. 

 They arise within an inch and a quarter of the large globular cloaca, and are very 

 short, measuring only about a fourth of an inch in total length. 



The "large" intestine is very short and perfectly straight. Its calibre is a little 

 greater than that of the ileum just anterior to the cfeca, but it is not as large in cir- 

 cumference as is the duodenum. It differs from the other portious of the intestine in 

 the thickness of its muscular walls, the increased amount of muscular tissue being 

 quite appreciable to the eye. 



After but a little more than an inch of length the colon terminates in the cloana. 

 This is exceetlingly capacious and distensible, measuring, when fully inflated, an inch 

 and three (juarters in length by one and a half in breadth. It is of a nearlj' globular 

 sha).>e ; its superior portion, however, being soniewliat conical aud tapering where it 

 contracts into the rectum. It is very slightly and incompletely divided into two ua- 



