1833.] of the second part Phys. Trans. 423 
being an accident, or lusus nature, of rare instead of, as was at one 
time supposed, constant occurrence. A doubt has been thrown upon 
Pennant from this circumstance, which he does not deserve, and 
which our author will be glad to have satisfactorily overthrown. 
Article XI. is an admirable description of the most splendid speci- 
men of all the known species of horn bill, the Buceros Homrai of 
Hopeson. To this description nothing can be added, comprising as it 
does every minute point, in age, sex, and variety. Four, perhaps five, 
species of Buceros may now be considered as belonging to continental 
India, and Mr. Hopnason seems to have established the fact of their 
all being strictly frugivorous ; and not partially carnivorous, as was 
erroneously supposed, from analogy with the Toucan. Indeed there is 
good reason to believe that this latter bird has been libelled ; the can- 
nibal propensities it has occasionally exhibited having been developed 
only in a state of confinement. 
An anatomical notice is affixed to the description by Mr. Bramtey, 
a gentleman whose numerous professional avocations are to be regret- 
ted as preventing him from devoting zoological talent of no ordinary 
standard entirely to scientific pursuits. The peculiarity in structure of 
the cranium mentioned by Mr. Bramtuey is the want of motion be- 
tween it and the bill. He might also have noticed another; in 
the internal cavity of the bill being almost filled with osseous reticula- 
tions, instead of, for the greater part, occupied with membranous 
cells, as is the case in most other species of this genus. Mr. Bram- 
Ley also notices the lax union of the dorsal vertebre, and in doing so, 
touches upon the doctrine of compensation. 
Of this doctrine it may be well to say a few words, especially as it 
seems to be daily gaining ground among certain speculative, but scien- 
tific men, of whom M. M. Cuasrier and Aupouin among the French, 
and MacLeay and Vicors among the English, are at present the ac- 
knowledged heads. Their great object is generalization, and the 
natural fondness of mankind for conjecture, their means. Their doc- 
trine may be stated in a few words. 
All animals have a determinate number of parts, differing only in the 
degree of development; the development of one organ exerting an in- 
verse influence upon another. 
So much for the ingenious and convenient doctrine of compensation. 
But to return to Mr. Bramuey, who in speaking of the bill of the 
Buceros Homrai remarks :— 
“<The casket (which is of large dimensions) has also its horny covering, though 
somewhat different in structure, that of the former being laminated and bearing a 
