136 
COMPARATIVE ANATOMY 
fish, which are obliged to rise every two or three minutes 
to the surface to take breath, the tail, unlike what it is in 
other fish, is horizontal; its stroke consequently perpen 
dicular to the horizon, which is the right direction foi 
sending the fish to the top, or carrying it down to the bot¬ 
tom. 
Regarding animals in their instruments of motion we 
have only followed the comparison through the first great 
division of animals into beasts, birds, and fish. If it were 
our intention to pursue the consideration farther, I should 
take in that generic distinction amongst birds, the web- 
foot of water-fowl. It is an instance which may be point¬ 
ed out to a child. The utility of the web to water-fowl, 
the inutility to land-fowl, are so obvious, that it seems im¬ 
possible to notice the difference without acknowledging 
the design. I am at a loss to know, how those who deny 
the agency of an intelligent Creator, dispose of this exam¬ 
ple. There is nothing in the action of swimming, as car¬ 
ried on by a bird upon the surface of the water, that should 
generate a membrane between the toes. As to that mem¬ 
brane, it is an exercise of constant resistance. The only 
supposition I can think of is, jhat all birds have been orig¬ 
inally water-fowl, and web-footed; that sparrows, hawks, 
linnets, &c. which frequent the land, have, in process 
of time, and in the course of many generations, had this 
part worn away by treading upon hard ground. To such 
evasive assumptions must atheism always have recourse! 
and, after all, it confesses that the structure of the feet 
of birds, in their original form, was critically adapted to 
their original destination! The web-feet of amphibious 
quadrupeds, seals, otters, &c. fall under the same obser¬ 
vation. 
IX. The five senses are common to most large ani¬ 
mals: nor have we much difference to remark in their con¬ 
stitution; or much, however, which is referable to mech¬ 
anism. 
The superior sagacity of animals which hunt their prey, 
and which, consequently, depend for their livelihood upon 
their nose, is well known in its use; but not at all known 
in the organization which produces it. 
The external ears of beasts of prey, of lions, tigers, 
wolves, have their trumpet part, or concavity, standing for¬ 
wards, to seize the sounds which are before them, viz. the 
sounds of the animals which they pursue or watch. The 
ears of animals of flight are turned backward, to give no¬ 
tice of the approach of their enemy from behind, whence 
