1905.] 



AXATOMY OF LTMICOLINE BIRDS. 



157 



and notably difierent fi-om that of the Oolumbfe, or, indeed, of any 

 other group except the Lari. The duodenal loop is simple and 

 definite (text-figs. 24 and 25, A-B) ; the portion of Meckel's tract 

 proximal to Meckel's diverticulum (Div.) tends to be enlarged in 

 such a way that the diverticuhim is not at the apex of a loop as 

 in Oolumbaj or Passeres, but on the distal limb of a loop, which 

 is short in the forms which are less specialised in this respect, 

 such as the Ohionidas, Glareolidte, Thinocoridpe, OEdicnemidse, 

 and the simpler Oharadiiida? (such as Numeimis and Vanellus), 



Text-fig. 24. 



Diagram of iutestiiial pattern of Ithyncli(ea cajoensis. 



A. Cut proximal end of duodenal loop. B. Distal end of duodenal loop. 

 Div. Meckel's diverticulum. C. Origin of creca. R. Cut end of rectum at cloaca. 



but which in other Charadriidse and Parridae (such as Scolojyax, 

 Himantopus, and Hydrophasiamis) is elongated and spirally 

 twisted. The portion of Meckel's tract between this and the 

 duodenal loop is ill-defined in the simpler forms, but in others 

 tends to be thrown into a definite narrow loop. The portion pos- 

 terior to the diverticulum is in close relation to the colic caeca, 

 which are long in the simpler forms (text-fig. 24, C), but become 



