The alligator and its allies . , come to the surface to breathe, withoutdanger of letting water into its trachea. The nasalpassages, leading from the nostrils to the posteriornares, are, of course, completely inclosed by bone, asdescribed in connection with the skull. Ventralto the larynx and posterior part of the mouth is thelarge, shield-shaped hyoid apparatus. Fig. 25, h,also described in connection with the skull. The CEsophagus The oesophagus. Fig. 34, e, is long and of aboutthe same diameter throughout except possibly fora slight enlargement of the anterior region where itleaves the phar
The alligator and its allies . , come to the surface to breathe, withoutdanger of letting water into its trachea. The nasalpassages, leading from the nostrils to the posteriornares, are, of course, completely inclosed by bone, asdescribed in connection with the skull. Ventralto the larynx and posterior part of the mouth is thelarge, shield-shaped hyoid apparatus. Fig. 25, h,also described in connection with the skull. The CEsophagus The oesophagus. Fig. 34, e, is long and of aboutthe same diameter throughout except possibly fora slight enlargement of the anterior region where itleaves the pharynx. The two olivary enlarge-ments mentioned by Chaffanjon (15) are notalways present, and when seen were found tocontain either food or small stones or both. The outside of the oesophagus is smooth andmuscular while the lining is thrown into numerouslongitudinal folds that in the empty oesophagusnearly obliterate the lumen; where distended by foodor pebbles the longitudinal folds may be almost 152 The Alligator and Its Allies. Fig. 34. Digestive System of A MiSSISSIPPIENSIS. bd, bile duct; 6s, bile sac; c, cloaca; e, oeso-phagus;/, larger or fun die region of stomach;/;, hyoid apparatus; /, liver; />. smaller orpyloric region of the stomach; pa, pancieas;r, lectum; s, small intestine; /, tongue; tr,trachea. obliterated. m athirty-inch animalthe oesophagus isabout six inches long,and opens suddenly,but without any ap-parent valve, into thelarge chamber of thestomach. The his-tology of the oesoph-agus and the otherregions of the diges-tive tract will be de-scribed later. The Stomach The stomach, as iswell known, is madeup of two distinctparts; that on theanimals left, intowhich the oesophagusopens, is many timeslarger than the partfrom which the smallintestine leads. Thelarger or jiuidic re-gion, Fig. 34, /, has,as will be described,very heavy muscular The Digestive System 153 walls. When empty the lining of this part ofthe stomach is thrown into a few comparativelylarge fold
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Keywords: ., bookcentury1900, bookdecade1910, bookpublishernewyo, bookyear1915
