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Show 310 DR. H. GADOW ON THE INTESTINAL [May 21, The Ratitee are a very heterogeneous group, because of the great diversity in the length and arrangement of the main gut and in the development of the caeca. In none of these birds has it come to the development of closed and well-defined loops of the mid-gut (with the exception of the duodenum). In this respect they represent the lowest type amongst the recent birds ; to connect them with the Reptiles would, however, be a far-fetched and futile attempt. Their connections with recent Carinatae are distant. Nearest of them to the latter comes Apteryx through more defined loops, and the Crypturi seem to represent the link. The Gallinae stand more distant. All the Ratitae agree with each other in having the second loop right-handed, and the third left-handed ; this is a feature which occurs again only in the Crypturi, Gallinae, Opisthocomus, and in the Cuculidae. The Gallinee form a well-defined group ; lowest among them stand the Neotropical Wood-fowls, and it is through them that they lead towards the Crypturi. The Gallinae have also an unmistakable resemblance to Opisthocomus and thence to the Cuculidae. The Turnic.es, to which belongs undoubtedly Pedionomus, are traceable to a Ralline or low Gralline stock, with assumed plagioccelous characters of the second loop. The periccelous assemblage is large. It is typically represented by the Grallee, of which the Limicolae and the Rallida**- form the principal groups. However, the configuration of their intestinal folds as well as numerous other characters separate these two groups sufficiently to give them equivalent rank. The Rallidce, to which belong the Alectorides, are connected with the Turnices, more distantly with the Crypturi, and still more so with Apteryx. Dicholophus is in all points a Gruine form, like Psophia, and cannot be separated from them. Rhinochetus contains Ralline, Limicoline, and Ibis-like features ; the only bird which it resembles somewhat closely in its very peculiar intestinal convolutions is Podica. The Limicolee agree with the Laridce, and also with the Columbce, in all essential points. Each of these three groups contains a number of forms which lead in an unbroken series from the typically periccelous birds with four alternating loops to the typically mesogyrous birds. Most Columbae and Laridae are mesogyrous : Sterna and its allies represent periccelous or lower forms. Neither granivorous, nor insectivorous, nor piscivorous habits have exerted any appreciable influence upon their intestinal convolutions, although of course the stomach and the caeca are affected. The presence of the crop of the Columbae is repeated in the granivorous limicoline genera Attagisand Thinocorys. It is interesting to note that Limosa and Numenius are both low Limicolae, and that Numenius approaches in various ways the Ibises, whence of course a continuous line can be traced into Platalea and Phcenicopterus on the one hand and into the Pelargi proper on the other. Rather different from the Limicolae are the Pteroclidce. They have four loops, which are all closed, left-handed, i. e. isoccelous, and straight; the second and fourth loops have their apices turned |