32 Lieut. W. V. Lcgge on the Distribution of 



general ; and I can safely vouch;, after a close examination of 

 the mandibles, that no signs of the space existed, nor was there 

 any serration of the edges or other indication of a probable 

 development from natural causes of this peculiar formation. 

 The edges of the mandibles fitted together as with ordinary 

 birds. The young of this Ibis, like those of Tantalus leuco- 

 cephalus, do not reach the full size until some time after they 

 *are fully fledged — in fact, not until the end of the first year. 

 They are differently clothed miniatures of the adult, so to 

 speak. Jcrdon mentions, ' Birds of India,^ vol. iii. p. 765, 

 that he is of opinion that the white birds seen now and then 

 are not young but old individuals ; his supposition would ap- 

 pear to be correct, as my specimen had the interscapular region 

 and about the shoulders brown instead of grey as in the adult, 

 the scapulars brownish black, and the head and neck dusky. 

 The length of the bill and tarsus were 4 inches and 5| as 

 against 6"1 inches and 6j respectively in the adult. In spite, 

 however, of the non-existence in the young bird of this cavity 

 (which I should be sorry to affirm was always the case on the 

 testimony of one example only), there is but little doubt that 

 it is developed naturally, and not by wear, at a more advanced 

 stage than that in which my specimen was ; for the peculiar 

 decomposed and fibrous-like process extending along the edge 

 of the " arch " on the margin of the upper mandible militates 

 against the idea that this is the result of friction in opening 

 shells. If it were so, this soft formation would soon cease to 

 exist, and the edge of the upper mandible wovild be as smooth 

 and hard as that of the lower. Assuming that this is the cor- 

 rect hypothesis, what is the object of this formation in the 

 economy of the bird ? 



Concerning our Laridse there is but little to note, as this 

 particular part of the coast is poor in variety of species, al- 

 though those which do visit us exist in large numbers. The 

 common Gull of the north, Xenia brunneicephalum, Jerdon, so 

 abundant about Trincomalie and Jaffna, I have only once seen 

 in this neighbourhood. Croicocephalus ichthyaetus is very rare 

 in this country so far south. I have but^once noticed it ; and 

 that was in the rough weather off" the coast at Colombo. The 



