OCR Text |
Show 1896.] INTESTINAL TRACT OF BIRDS. 157 type. The wide gut is very short: the Colies, for instance, have shortest guts of any birds that I have examined ; but the same general features are present in all. Rhytidoceros plicatus, for instance (fig. 23), shows the duodenum as a very wide irregular Fig. 23. Rhytidoceros plicatus ; intestinal tract. loop, with a pucker at its closed end. The circular part of the gut is thrown into three simple subsidiary folds. The first of these corresponds to that present in most Owls, but absent in the Eagle- Owl; the second bears the yolk-sac vestige at its extremity, and the third corresponds to the part along which the lost caeca lay. The rectum is straight. The veins are in the typical form, and I have not found any short-circuiting veins. In the Woodpeckers (Gecinus) and Toucans (Rhamphastos) the duodenum is equally wide: the three loops of the mid-gut are present with the yolk-sac vestige on the median loop ; but all three loops are much wider and shallower than in the Hornbill. The Fig. 24. Colius capcnsis ; intestinal tract. |