INTESTINAL THACT OF BIRDS. 



223 



tally with the figure. The differences which occur among the Rallidae are insignificant ; 

 in some, there are two " bridging " veins, in some, one ; the Meckel's diverticulum, which 

 is always large, may be extremely large, the size of this structure being a characteristic 

 feature of the group ; the third svibsidiary loop of Meckel's tract occasionally is relatively 

 smaller than the other loops. 



(1) Gruina>. In Grus viryo (fig. 42) and other species of Grus, and species of 

 Anthropoidcs and Balearica are practically identical, the large size has brought with 

 it a relatively great increase of length, but the fundamental identity of the conformation 

 of the gut with that exhibited by the Bails is obvious. The duodenum is similar, 



Fig. 42. 



Intestinal Tract of Grus virgo. Lettering as in fig. 41. 



although, on account of its great length, it is partly bent. Meckel's tract displays the 

 same four loops : " " being widened out ; " b" the axial loop being very lonij but carrying 

 a Meckel's diverticulum in the characteristic position, on the distal limb of the loop ; 

 " c" being small but compound; and the supra-duodenal loop to which the long caeca 

 are attached being much enlarged. It is plain that w r e have here a simple modification 

 of the Balline pattern, the modification being due to the relatively greater length of gut 

 that occurs in larger birds. 



(2) Aramince.- The very interesting form Aramus scolopaceua (fig. 43) displays a 

 conformation of the intestinal tract which differs only in minor respects from that in the 



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