144 ME. *. OHAtiMEES MlMHEtL ON THE [Jan. 14, 



gated, the greater part of the elongation having occurred in the 

 circular loop. The caeca are small, and lie on the third part of 

 the gut, some distance below where it joins the circular loop, 

 As usually happens when the ca5ca are reduced, the last part of 

 the circular loop is pulled out into a long free loop, which, in the 

 natural position, is closely attached to the under surface of the 

 duodenum, and gives a vein to the duodenal vein. Platalea leuco- 



Platalea leucorodia ; iutestiiml tract, x, short-circuiting vessel cut across. 



rodia, the Spoonbill (fig. 8), shows the least differentiation among 

 those that I have examined. The duodenum is very long and is 

 curved far round to the left in the abdominal cavity. The circular 

 loop is enormously expanded, and forms a rough spii'al, of which 

 the middle mesenteric vein, running out to the vestige of the yolk- 

 duct, forms the axis. The iigure represents this after it has been 

 dissected out and is more diagrammatic than most of the drawings 

 I give. The most important points to which I would call attention 

 iire : that the yolk vestige, though at the end of the spiral, is much 

 nearer the posterior than the anterior end of the circular loop, 

 owing to the greater development of the first half of the circular 

 loop ; and the fact that on the whole the minor loops of the 

 circular loop are of similar length, -with the exception of the last 

 loop. It is in this respect especially that the Spoonbill lias departed 

 less than other Ciconiiformes from the type. The veins of the gut 

 are almost diagrammatic in the simplicity of their arrangement, 

 the only peculiarity being the short-circuiting branch from the 

 duodenal vein to the distal loop of the circular loop. 



In Pseudotantalus ibis the duodenum, which was curved in 

 Platalea, is very much elongated and twisted into a spiral. The 

 first portion of the circular loop is elongated into a separate 

 loop : the remainder of the circular loop is more primitive 

 even than in Platalea, consisting of a number of nearly equal 

 radial folds at the circumference of the whole fold. There is & very 



