of certain Birds of Cuba. 45 
suck insects out of flowers with the nectar; but the reason of 
the difference between them is, that the Humming Bird contents 
itself with soft Tpulide, while the Pendulinus digests hard Hy- 
menoptera. ‘Chat the Trochilide should take animal food, we 
perceive from their analogy to the Hirundinide on the one side ; 
and that they should also take vegetable aliment, we understand 
from their analogy to the Psittacide on the other. With both the 
Hirundinide and Psittacide it agrees in that peculiar anatomical 
. characteristic, of wanting an emargination to the sternum. 
While on the subject of analogies, I may be allowed to men- 
tion a series, which, although it is directly deducible from his 
diagrams, is not expressly mentioned at length by Mr. Vigors. 
It is valuable, inasmuch as it may serve to show that the per- 
fection of ornithological structure and intelligence lies among 
the Scansores. Mr. Vigors has proved by a chain of examples, 
that the five groups of Insessores represent the five primary 
groups or orders of Birds; and so also it would appear that 
the five groups of Scansores represent the five groups of Inses- 
sores, and consequently the orders of Birds. For instance, 
Toucans belong to the group of Insessores, so that on this point 
nothing need be said; but every one must have also remarked 
the form of beak and prehensile foot of the Parrot to give it an 
analogy to the Birds of Prey*. 
The backward position of the legs, with reference to the ster- 
num, and the disappearance of the hind toe, with other points 
of structure in certain species of Picide, give a common cha- 
racter of analogy to them and the Natatorest. The length and 
curvature 
* «Tnitium facere lubet 4 Psittaco quam curvirostrem avem et instructam cerA qua 
Striges Laniique carent, primo loco post Accipitres ipse quoque Linnaeus posuit, quin 
olim cum lis quoque invita licet natura conjunxerat.” Herm. Tab. Aff. Anim. p. 181. 
+ This analogy is the origin of such specific names as Alca Psittacuia and Alca 
Pica. Hermann says, p. 156: “ Pelecanus Carbo rigida cauda quam solis cum Plotis 
communem 
