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Show 1880.] OF THE STOMACH IN TANAGERS. 145 pyloric ends of the stomach that obtains in most other birds. ~\~ere f *s n o trace °f a n y external diverticulum to be seen; and I therefore can only conclude that Lund must have been misled, he, owing to the bad condition of his specimens (a very probable contingency when dissections are made in tropical climates), having mistaken a bit of fat or connective tissue for a diverticulum of the ven-triculus, which last there can be no doubt that this non-glandular zone really represents, the muscular walls and hard epithelium of the true Passerine gizzard being almost entirely undevelopedl. Fig. 2. sm.i Stomach of Euphonia violacea. A portion of the alimentary canal of Euphonia violacea, twice the natural size, cut open and seen from behind, to show the proventriculus (p), the narrow zone representing the gizzard (z.), and the commencement of the small intestine (sm.i). The liver and spleen are also seen, as is the end of the oesophagus, which is opened up. I have also been able to ascertain that the nearly allied genus Chlorophonia (at least in C. viridis) is characterized by the same non-development of a gizzard. On the other hand, all Tanagers yet examined belonging to other than these two genera have stomachs constructed on the normal type. Thus in a specimen oi Tachyphonus melaleucus (see fig. 1, p. 143) the characteristic gizzard with the two central tendons is present and well developed, the muscular walls being nearly 4; inch thick, and the epithelium lining it hard and horny. As might have been expected, considerable variations in the comparative development of these parts occur in different genera. Thus in the thick-billed Pitylus the whole organ is m u c h more strongly 1 In confirmation of the above-mentioned view being correct, I m a y notice that neither Owen (Anat. Vert. ii. p. 106) nor Gadow (Jen. Zeitschr. B. xiii. p. 168, 1879), when mentioning the stomach of Euphonia, describe any lateral diverticulum.' Prof. Garrod, in his MS., notes of Euphonia violacea, with characteristic terseness, " N o stomach specialized, the intestines apparently continuing from the oesophagus." 1 0* |
