143 Anatom'icat Ohervatiovs on 



strongly distended, and made to vibrate in the manner df 

 the parchment of a drum, by the interior air of the lungs, 

 which causes the crocodile to emit that crv, or rather that 

 bellowing noise, mentioned bv Catesby, La Coudreniere, 

 and Bartrani. The fissure of the glottis is then shut by the^ 

 muscular roll which borders it on each side* 



The lungs are two conical bags, the summits of which are 

 turned towards the head. Their interior surfaces, which rest 

 on the oesophagus, retain the impression of it by a longitu- 

 dinal furrow. Tiieir length is 0*33 metre, and their breadth 

 at the base 0'23. The figure given by Perrault represents 

 them of an elongated ovoid form. 



The lungs of lizards are only two elongated bags, 0'40 in 

 length, and O* 1 1 in their greatest thickness ; the interior 

 sides of which are lined with small reticular carneous 

 fibres and sanguiferous vessels. Those of crocodiles diflTer 

 by the size of the membranous leaves with which they are 

 furnished, and which form as it were several small walls. 

 It is a vast reticulation, composed of a quantity of meshes 

 similar to those whish are seen in the second stomach of 

 ruminating animals. P^ach of these meshes is the edge and 

 entrance of a small bag, which opens into a second, and 

 sometimes into a third. They arc composed of two kinds of 

 fibres : the first circular, and parallel to each other; the se-* 

 cond perpendicular, which transversely intersect the former 

 at right angles. The centre of each pulmonary bag, en- 

 trrely empty, serves in some measure as a receptacle for the 

 air. The cells in opening become filled with it. They then 

 compress it by shutting, and convey it to the blood, as we 

 may say, without the concurrence of those organs which 

 press on the whole pulmonary mass. They repeat this play 

 until the air contained in the whole lung is vitiated. The 

 crocodile, then, is not forced to come and respire at the sur- 

 face of the water till after a certain time has elapsed. This 

 structure of the lungs, which makes the crocodile deviate 

 from lizards, brings it near to the sea-tortoise. I shall have 

 occasion hereafter to remark, that this is not the only rela- 

 tion which it has to these animals. 



IV. Of the Organs of GcJieratwn. 

 These organs are so complex, and have so little relatiort 

 to v.'hat is known in the mammalia, that authors, as we may 

 say, have been afraid to describe them, and have scarcely 

 civen a slight sketch of them. It has been said that the 

 crocodile is onlv a lizard of a monstrous size, and Linnaeus 

 ,Jias consequently arranged it in his system under the genus 



lacerta^ 



1 



