32 CURL. 



bill, at least in captivity, never has any fat about him." The species 

 mentioned is often found to be extremely fat and it takes a long time 

 to remove the thick layer from the skin, while the abdomen contains fat 

 in quantities. In other specimens collected under similar conditions, 

 very little fat is present. Again, the statement that the large hornbills 

 make so much noise when flying that they "can be heard a mUe," does 

 not apply to the bird mentioned. 



The most important tiling which my findings tend to show to be in 

 error, is regarding the muscular layers of the intestine. Authorities 

 make the general statement that the circular layer of the intestine is 

 found external to the longitudinal layer, as in the oesophagus. This is 

 true in some birds, but in many it is by no means so. In Hydrocorax^ 

 in ^theopsar, in Anas, and in Bubulcus, the Tan Gieson stain shows 

 clearly that the intestine has an outer longitudinal layer of muscle in 

 contact with the peritoneum; next, internal to this, a circular layer 

 and still more internally, a thinner longitudinal layer, with some oblique 

 fiibers and intimately blended with the submucosa. This last layer of 

 muscle corresponds very closely to the muscularis mucos£e in mammals 

 and is sometimes so developed as to become a fairly thick longitudinal 

 layer. These layers are shown very clearly in the photomicrograph of 

 the intestine of Hydrocorax hydrocorax. Anyone familiar with histo- 

 logical technique can verify the above in the genera mentioned, and I 

 dare say in many others by using a two-thirds inch objective for routine 

 and one-sixth inch for occasional differentiating. 



In the following descriptions of the parts of the alimentarj" tract, 

 the measurements given are from alcoholic specimens, previouslj'' run 

 through the 10 per cent formalin and are slightly less than those from 

 fresh material. The cesophagus, proventriculus, stomach, and intestine 

 are described and photomicrographs given to show the histology". 



The oesophagus is 200 millimeters in length and will admit the tliumb 

 when fully dilated; at the lower end it becomes funnel-shaped and 

 increases in size as it reaches the proventriculus. The mucous mem- 

 brane is thrown into longitudinal corrugations which ran unbroken for 

 almost the entire length; these corrugations project further into the 

 lumen in front than behind throughout the upper three-fourths ; in the 

 lower fourth, they are of about equal size on all sides. Dilatation of 

 the oesophagus does not obliterate them and the best-developed ones 

 measure 3 millimeters in height. 



A cross section shows microscopically that there is an external, circular, 

 muscular layer ; next, an internal, longitudinal layer intimately connected 

 with the mucosa, in fact projecting inward into the bases of the rugs. 



The mucous membrane being thrown into longitudinal corrugations, 

 a cross section gives a circle of inward projections with connective tissue 

 frame work, the usual blood vessels, and covered with epithelium. A 

 layer of globular cells lies beneath the epithelium and each opens by a 



