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Show 1882.] DR. GADOW ON THE ANATOMY OF PTEROCLES. 329 tively short gut, these two loops are very short, and are stowed on the right side of the abdominal cavity ; when the ileum is relatively 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 ca?ca; the 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. W e meet with a totally different arrangement in the Columba?. 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 Carpophaga latrans) extremely short, is entirely coiled up into a left-handed spiral. As a rule there are in this spiral 3 direct and 2 retrograde 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 3| 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, entirely 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 drinking, 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 ; while according to Radde Syr- |
