1882.] DR. GADOW ON THE ANATOMY OF PTEROCLES. 329 



tively short gut, these two loops are very short, and are stowed away 

 on the right side of the abdominal cavity ; when the ileum is re- 

 latively long, the number of the loops is not increased nor do the 

 two loops grow in a straight direction, but the apex of each turns 

 backwards so as to give the loops a horseshoe shape. The fourth 

 loop is formed by the last third of the ileum, and is accompanied by 

 the cseca ; tiie whole loop is never a " closed " one, its terminal 

 branch is nearly straight, the other one much shorter and, if the 

 gut be long, irregularly curled. 



We meet with a totally different arrangement in the Columbae. 

 There are invariably only three loops formed by the intestinal tract. 

 The first, the duodenum, is very wide, and sacculated at the apex. 

 The second is very long, and, in all those species where the total 

 length of the intestine is not (as for instance in the fruit-eating 

 Carpo])haga latrans) extremely short, is entirely coiled up into a left- 

 handed spiral. As a rule there are in this spiral 3 direct and 2 re- 

 trograde turns ; the number of these, however, wholly depends on the 

 relative length of the ileum : thus in the common Pigeon, with the 

 relative length of the gut about 12, the apex of the ileum-loop 

 has turned round Sg times ; whilst in others, like Chalcophaps, the 

 number is less ; and, lastly, in Pigeons with very short guts, as in 

 Carpophaga, a spiral is not developed at all (because, as far as we 

 know at present, the intestinal spiral in certain birds is only one 

 of the means of stowing away the longitudinally growing gut). But 

 it must not be forgotten that in Columba as well as in Carpophaga, 

 whether the ileum be long or short, we never have more or less than 

 three folds. The last, or third loop is a very long one too, en- 

 tirely closed or double throughout its whole length. 



Mode of Life and Propagation. 



The Sand-Grouse differ greatly from the Pigeons in their mode of 

 drinking. It is well known that the latter, during the act of drink- 

 ing, dip their bill into the water as far as the cleft of the mouth, and 

 then suck the water in without raising their head till they have 

 finished drinking. Pterocles and Syrrhaptes, on the other hand, 

 drink as Fowls and other birds do, by taking up water mouthful by 

 mouthful and letting it run down the throat. This peculiarity is 

 probably the result of a special mechanism of the muscles of the 

 throat and glottis, but is as yet unexplained. 



Their flight consists of rapid uniform movements of the wings, 

 and generally resembles that of the Pigeons more than that of the 

 Plovers ; but they do not glide or soar as the Pigeons do. 



From their voice we cannot gather much information as to their 

 affinities ; but certainly they do not coo. 



During the greater part of the year they are gregarious. They 

 are monogamous like Pigeons and Plovers, differing in this respect 

 greatly from the Rasores, which are typically polygamous. Their 

 nest is extremely simple and situated on the ground. The number 

 of eggs laid by Pterocles is three ; wliile according to Radde Syr- 



