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 Ungues 

 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 Eupo- 

 dotis australis. 



In a specimen of the head of Otis tarda in the Museum of the 

 College of Surgeons t the frenum linguce is median and normal in all 

 respects. The sex is not mentioned ; but from the fact of its 

 differing so much from that of my 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 

 my surmise is not absolute. 



The two sublingual frena, with a membrane between them, make 

 it seem almost certain to me 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 di- 

 verticulum in the specimen figured in my previous paper on the 

 subject ; for, from the absence of any trace of a crop in the young 

 bird, it may 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 my earlier communication and that 

 described in the present may all be seen in the Museum of the College 

 of Surgeons. 



* P. Z. S. 1874, p. 472. t No. 772 Q. 



