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DE. P. CHALMERS MITCHELL ON THE 



that found among the Cuculidse. In these, as we have seen, the tendency is for the 

 anterior portion of Meckel's tract to be produced into two loops, and this mode of 

 apocentricity is typical of Coraciiform birds. The reduced gut of the Musophagidae 

 might have come from any simple source. The Psittaci live largely on hard grains and 



Intestinal Tract of Stringops habroplilus. 



a, b, c and S.D.F. are the four loops of Meckel's Tract typical of the Psittaci ; a, i, and c being 

 here subdivided, while S.D.F. is a supra-duodenal loop. 



seeds, and this habit, together with the large size of many of the forms, has no doubt 

 greatly added to the length of the gut and helped to disguise its morphological form. 

 That conformation is markedly apocentric, as shown by the complicated folding of the 

 loops, the length of the loops, the individuality of the supra-duodenal loop, and the 

 absence of caeca. No doubt such a type might have been derived independently from 

 any of the more arcliecentric forms, from, for instance, some of the simpler Galli, as has 

 been suggested, but it is equally easy and perhaps more natural to derive the Psittacine 

 type from that occurring in the simpler Coraciiform birds. 



