ox HIE nESPIRATlON OF FISHES. 353 



now known, that the respiration of the batrachian reptile* 

 is effected by means of the muscles of the throat,, and the 

 clastic plate of the hyoides, which perform the office of 

 ribs and diaphragm. And for inspiration thus to take 

 place, the month must previously be closed; so that if an 

 adult salamander or frog were placed in water, with the 

 mouth kept open by force, or eyen left so in the moist and - 

 open air, it would soon die of suffocation. In all thesO 

 animals the air is expelled suddenly from the Mings by the 

 action of the abdominal muscles. It issues from the mouth 

 in Tery large bubbles, and by a sort of vomiting, which 

 explains the force and continuance of their croaking, even 

 under water, as is observed in a great many species. 



All the chelonian reptiles are circumstanced precisely as Tortoises, 

 the batrachian. Not that the tortoises for instance are 

 destitute of ribs, or sternum, as no animals hare these 

 parts more solid and distinct. But all these ribs are 

 united to the vertebraj «nd to each other, to form that bony 

 shell, which covers their muscles, limbs, and viscera, in 

 the back ; as the parts of the sternum spread abroad cover 

 them on the belly. 



I believe I first demonstrated in my public lectures, on Mistake of 



living tortoises, the mistake of Townson in his examination Townson re- 

 /.,,-.. specting their 



of the mechanism of respiration in a tortoise, the under breathing. 



shell of which he had removed, and in which the mecha- 

 nical action of the lungs was still exerted. This gentle- 

 man ascribes the faculty of drawing the lungs outward to 

 two muscles, which can only compress them; while the 

 motion of the throat, and the complete cessation of the 

 act of inspiring when the mqiuth is open, would have givea 

 him a better insight into the true mechanism of this func- 

 tion, and the analogy that exists in this respect between tor- 

 toises and frogs. Indeed this is an observation, to which 

 we aie naturally led ; and Mr. Cavier, who has verified it, 

 adopts the same opinion in his Lectures on Comparative 

 Anatomy, vol. iv, p. 368. 



Here then we find the act of respiration performed in Still these re- 

 certain reptiles differently from what it is in animals tlia^bv^a different 

 seem to precede them immediately in the scale of beings, mechanism. 

 Yet, though the mechanism is different,* the effect is nearly 



Vol. XXyill, Supplement. A a th« 



