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Show 674 MR. GARROD ON THE " SHOW-OFF " IN BUSTARDS. [DeC 1, been in the possession of the Society between three and four months, had never shown off, and had no lateral tuft of feathers from the sides of the lower jaw. In it the oesophagus was uniformly cylindrical, with no trace of a crop, and there was no gular pouch. On looking under the tongue, however, it was evident that the arrangement of the sublingual structures was quite peculiar. In the male of Eupodotis australis, as I have previously remarked*, the frenum lingua is well developed in the normal manner as a median vertical fold; and, what is more, it is situated as far forward as in most animals, not behind the level of the basihyal apparatus. In the young and pouchless male of Otis tarda the condition is very different. In it the frenum lingua does not exist as such, but as two slight lateral vertical folds, with a median interval between them, a quarter of an inch across ; so that the pouchless sublingual region of the young male Otis tarda is very like the excellent drawing of that of the pouched adult male in Dr. Murie's paper on the bird (P. Z. S. 1869, p. 141), except that what is there represented as an aperture to a pouch must be considered for the time being as only a slight depression. The tongue is also free for a considerably further distance along its under surface than in Eupodotis australis. In a specimen of the head of Otis tarda in the Museum of the College of Surgeons t the frenum lingua is median and normal in all respects. The sex is not mentioned; but from the fact of its differing so much from that of m y young male specimen, I cannot help inferring that it is that of a female. If such is the case, until more examples are obtainable, the certainty as to the correctness of m y surmise is not absolute. The two sublingual frena, with a membrane between them, make it seem almost certain to m e that in the adolescent male bird, and not in the female, there is every opportunity for the development of a pouch, and that the habit of inflating the air-passages during the sexual season distends the membrane between the frena linguae, it being comparatively weak, and causes it to develop into a pouch from continued stretching. In favour of the here assumed existence of considerable pressure is the existence of the abnormally situated diverticulum in the specimen figured in m y previous paper on the subject; for, from the absence of any trace of a crop in the young bird, it m ay be inferred that such an organ does not pertain to the species ; therefore it must be the result of some superadded force, brought into action in the adult, the distention of the pharynx during the " show-off" being quite sufficient to account for it. The specimens figured in m y earlier communication and that described in the present m a y all be seen in the Museum of the College of Surgeons. * P. Z. S. 1874, p. 472. t No. 772 Q. |
