NATURAL THEOLOGY. 259 



doubted of? Nor is it a mere doubling of the 

 skin ; but is a new organ, furnished with bones 

 and muscles of its own. Two bones are placed 

 before the os pubis, and joined to that bone as 

 their base. These support and give a fixture to 

 the muscles which serve to open the bag. To 

 these muscles there are antagonists, which serve 

 in the same manner to shut it ; and this office they 

 perform so exactly, that, in the living animal, the 

 opening can scarcely be discerned, except when 

 the sides are forcibly drawn asunder.* Is there 

 any action in this part of the animal, any process 

 arising from that action, by which these members 

 could be formed ? any account to be given of the 

 formation, except design ? 



III. As a particularity, yet appertaining to more 

 species than one, and also as strictly mechanical, 

 we may notice a circumstance in the structure of 

 the claws of certain birds. The middle claw of 

 the heron and cormorant is toothed and notched 

 like a saw. These birds are great fishers, and 

 these notches assist them in holding their slippery 

 prey. The use is evident ; but the structure such, 

 as cannot at all be accounted for by the effort of 

 the animal, or the exercise of the part. Some 

 other fishing birds have these notches in their 

 hills ; and for the same purpose. The gannet, or 

 Soland goose, has the side of its bill irregularly 

 jagged, that it may hold its prey the faster. Nor 



♦ Goldsmith, Nat. Hist, vol iv. p. 244. 



