32 
Lieut. W. V. Legge 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. Jerdon mentions, c 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 6T 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 99 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 would 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, Xema 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 butonce noticed it; and 
that was in the rough weather off the coast at Colombo. The 
