PICAIU^ 



IV. — The caeca are two little blind tubes springiug 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. 



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

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

 across the middle line: jur^), maxillo-palatines; ^ja, palatine : si37t.r,_sphenoidal 

 rostrum; ^j^g^, pterygoid; h.ptg.pr, basi-pterygoid process of the basi- sphenoid ; 

 h.sph, 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 : — 



