246 ON THE “ SHOW-OF” IN BUSTARDS. 
basihyal apparatus. In the young and pouchless male of Otis tarda 
the condition is very different. In it the frenum lingue 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 excel- 
lent drawing of that of the pouched adult male in Dr. Murie’s paper 
on the bird (“ Proceedings of the Zoological Society,’ 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* the freenum lingus is median and normal in all 
respects. The sex is not mentioned; but from the fact of its differ- 
ing 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 lingue, 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 specimen figured in my earlier communication and that 
described in the present may all be seen in the Museum of the College 
of Surgeons. 
* No. 772 Q. 
