80 THE COLUMBID.E. 



without exception, short wings, the hand bones, collectively, being shorter than 

 the humerus. 



The sternum of Pigeons has one moderately deep notch or emargination on its 

 exterior edge, and one shallow one, or in many instances only a small hole 

 pierced near the posterior edge. — The sterna of all Gallinaceous birds have two 

 very deep emarginations on each side. 



The keel in Pigeons is very much rounded off at its anterior extremity, is of 

 great depth, and extends as far forwards as the anterior point of the sterna. — 

 In Gallinaceous birds the keel approaches much nearer to a straight line , is of 

 less proportional depth, and terminating generally in a p oint ; though the Cracidce 

 certainly have the keel more resembling that of the Pigeon, than the other classes. 

 The keel seldom exceeds two-thirds the length of the sternum ; in some instances 

 it is not much more than half the length, and it never reaches nearly to its an- 

 terior extremity. 



In Pigeons the hind toe is placed at the bottom of the tarsus, on a level with 

 the front toes, as obtains in the Insessores, and the front toes have no connecting 

 membrane. — Gallinaceous birds (I believe), with the single exception of the 

 Guan, have the hind toe situated higher than the front toes, which are always 

 united by a membrane. 



The Columbidce have the heart proportionably larger than the Rasores. — 

 Cuvier says, when speaking of the intestines of birds :• — " Birds generally have 

 two cseca, which insert themselves on each side of the intestinal canal ; in om- 

 nivorous and graminivorous birds, they are usually long and of great size." Here 

 I think he speaks rather too generally. I have examined several species and 

 some genera of the Columbidce, which are peculiarly graminivorous ; most of them 

 entirely want the caeca ; and where they exist, they are so small as? to be nearly 

 microscopic. 



In all the Rasores which I have examined, the caeca are considerably developed ; 

 in the Red Grouse these organs are very large, — affording a wise and seasonable 

 provision for those privations to which the birds are subjected during periods of 

 continuous snow. 



I have no intestines of the Curasow, the Guan, or the Crowned Pigeon ; but 

 as the two former approach the other Rasores so nearly in the form of their 

 skeletons, I assume that their caeca and crops would follow the same type ; and as 

 the skeleton of the Crowned Pigeon so nearly resembles that of the typical 

 JColvmbidce, I presume that, like them, it will want the cseca. — I regret not 

 having preserved the intestines of these birds ; but when I began preparing skele- 

 tons of birds, I was so occupied with the bony structure, that I attended to no 

 other trait of their anatomy. Such, I believe, is often the case on taking up a 

 new subject; we know not what is likely to be useful, and often throw away 



