IV. The caeca are two little blind tubes springing from the 

 intestine at the commencement of the rectum or hinder part of the 

 gut. In a broad way they are best developed in purely herbivorous 

 birds, and small or short in meat- and fruit- eaters ; sometimes they 

 are entirely absent. 



,/rrvocfo. 



FIG. 5. Base of the skull of Scrpentarius secretarius, showing the desmo- 

 gnathous arrangement of the palate bones, the rnaxillo -palatines being coalesced 

 across the middle line: mrp, maxillo-palatines ; pa, palatine : sph.r, sphenoidal 

 rostrum; ptg, pterygoid ; b.ptg.pr, basi-pterygoid process of the basi- sphenoid ; 

 b.spli, basi-spheuoid. 



V. Huxley first pointed out the value of the arrangement of 

 bones of the palate as an important character in classification. He 

 distinguished four types of modifications as follows : 



