INTESTINAL TRACT OF BIRDS. 



195 



ARDE.E. 



(1) SCOPID^E. In Scopus umbretta (fig. 16) the duodenum is long and slightly twisted. 

 Meckel's tract is nearly symmetrical, a large Meckel's diverticulum being near the centre 

 of its periphery, and is expanded into a number of wide, irregular, but in the main straight 

 minor loops, the last of these being longer and forming a typical supra-duodenal loop. 

 The rectum is straight, of moderate length, and the pair of cseca are reduced. The veins 



are typical, 

 kink. 



A small area supplied by the rectal vein corresponds to the supra-caecal 



Fig. 16. 



Intestinal Tract of Scopus umbrettd. Lettering as before. 



(2) ARDEID^;. In the Herons and Bitterns, of which I have examined a number of 

 species, the ground-form is like that in Scopus. The duodenum is a long narrow loop, 

 nearly always considerably twisted to the left, usually more so than appears in the two 

 figures (Nycticorax griseus, fig. 17, and Ardea candidissima, fig. 18). Meckel's tract 

 may be rather elongated as in Nycticorax, or relatively shorter as in Ardea. It is 

 always drawn out into a large number of minor loops, many of which are irregularly 

 folded, and not infrequently complex in themselves ; the distal minor loops in Ardea 

 (fig. 18) show this in a relatively simple form. In the Little Bittern and some other 



