the Family of Cuculidce. 219 
divisions of the tribe unite among themselves, and form a circle of 
affinity, and I shall then endeavour to trace the same principle of 
circularity in such of the minor groups or sub-families as are most 
abundant in species. 
Commencing with the Picidce or woodpeckers, which are obvi- 
ously the pre-eminent type of the scansorial birds, we see a gra- 
dual approximation towards the soft tail, the green, bright-coloured 
plumage, and the curved, toothed bill of the parrots in the barbuts 
(Bucco,) and the tooth-bills (Pogonias, L.) The first of these genera 
so much resemble the Psittacidce in the style and similarity of their 
colouring that they might be taken for parrots, if their bills and feet 
did not evince an equal relation to the woodpeckers. The asser- 
tion of M. Temminck, that these birds do not climb,* is completely 
disproved by Mr Burchell, who assures me, from his personal obser- 
vations, they have nearly the same scansorial habits as the Piciance, 
a fact confirmed, indeed, by the structure of their feet. Next to 
these we have the genus Pogonias, whose short, curved, and toothed 
bill brings us so close to the Psittacidce, that one genus more would 
render the union of these families complete ; although it is even now 
so obvious that no question can be raised on this point. Leaving 
the Psittacidce, we enter among the toucans, by the green-coloured 
Aracaris, which have very properly been lately separated as a dis- 
tinct group : these birds, in short, connect the toucans to the par- 
rots in the same manner as Pogonias unites the parrots with the wood- 
peckers. It is thus we enter the family of the Ramphastidce or tou- 
cans, the fissirostral division of the Scansores, where, as in all perfect 
fissirostral types, we have great bulk, a very large or wide mouth, 
and small syndactyle feet, that is, with the toes more or less unit- 
ed. I may here advert to a fact in the economy of the toucans 
hitherto unpublished, and which gives an additional confirmation of 
their affinity to the Psittacidce. Many, if not all, of the parrots, as 
it is well known, employ their hooked bill as an organ of prehen- 
sion. My observations on the toucans of Brazil lead me to believe 
that they occasionally do the same, while climbing among the en- 
tangled foliage and branches in search of birds' nests, from which 
they greedily snatch either the eggs or the young. The Australian 
Sythrops, or channelbill, is a cuckoo, with the bill of a toucan ; 
and thus we pass from one family to the other so gradually, that 
analysis alone can determine to which this singular genus belongs. 
* M. Temminck gives no authority for this opinion, which must have been 
copied from other authors, he himself never having travelled out of Europe. 
