THE BIRDS OF AUSTRALIA. 
forms only. As a matter of fact, four species only are valid and they do not 
appear to be congeneric, unless we admit that they represent purely a colour 
genus and ignore structure. The history of the genus-name Calyptorhynchus 
has already been given in connection with the genus-name Trichoglossus, but in 
the present case the valid introduction of the genus Calyptorhynchus dates 
from Desmarest, as on p. 20, though he only wrote : “ Le genre Calyptor- 
hynchus Horsfield est compose des kakatoes noirs, a bee bombe de la Nouvelle 
Hollande,” on p. 117 he separated a section — “ *** A plumage generalement 
brun ou noir,” thereunder classing galeatus, funereus , temminckii, banksii, 
and leachii , and observed in a footnote : “II est vraisemblable que les oiseaux 
compris dans cette petite subdivision, composent le genre Calyptorhynchus 
de M. Horsfield, et qu’ils sont ainsi nommes d’apres la forme tres elargie et 
bombee de leur bee.” 
If we accepted this diagnosis of the genus, the two species baudinii and 
funereus must be at once dismissed, as their bills are very narrow and elongate, 
quite unlike the bills of the species banksii and lathami ( =viridis auct.). 
We have, therefore, to consider whether we will admit colour as the 
major item in the recognition of generic forms or subordinate it to structure. 
If we do either, we must still recognise two “ subgeneric ” groups, as the 
differences in the bill formation are too great to be ignored by any systematic 
worker. Further, there is little doubt that they are correlated with 
anatomical differences. When D’Arcy Thompson wrote upon the skull- 
characters of the Parrots in the paper already cited, he was not aware of the 
great appreciable differences in these species and consequently noted with 
surprise that his results on “ banksii ” did not agree with some recorded by 
another worker years before in connection with xanthonotus. A careful 
comparison would probably show many contradictory items, as it is rather 
obvious that the skull characters must disagree, judging from external 
features alone. Admitting that we have two forms in the “ genus,” one 
with narrow bills, the other with swollen bills, attention may be drawn to 
the fact that the two with swollen bills also differ appreciably. The typical 
form has the upper-mandible swollen, but looking at it from above the 
rounded culmen ridge has exactly the appearance of being made up of two 
pieces, a minute groove being observed down the centre of the ridge. The 
other species, lathami ( = viridis auct.) has a sharp keel to the culmen ridge 
and the under-mandible is much more swollen proportionately. Here 
again we have a peculiar difference observed, and when we examine the wing 
we see that it has developed a different wing formula, though the wing of 
the narrow-billed group ( baudinii and funereus ) has not varied from that of 
the typical banksii ; again, these are equivalent in size, while lathami has 
96 
