SIREN. 395 



These internal or posterior openings are entirely out of the direction 

 of the air from the lungs ; therefore it can hardly be supposed that they 

 respire through them ; and from this circumstance of their not being 

 perfectly adapted for air in respiration, we may suppose they also smell 

 in the water as fish do, especially as they breathe both water and air. 



On the posterior and lateral parts of the mouth, or fauces, are three 

 openings on each side ; these are similar to the slits of the gills of fish ; 

 but their partitions do not resemble gills on their outer edges or inner 

 surfaces ; for they have not the comb-like structure. Above, and close 

 to the extremity of these openings, arise so many processes ; the anterior 

 the smallest, the posterior the largest : the inferior edges through their 

 whole length, are slit, or are double ; the superior or anterior division 

 being the broadest ; and both are serrated, or formed into a kind of 

 fimbria : those processes can be folded down, so as to cover the slits 

 externally. The sulcus between the two edges is villous on the surface ; 

 and each sulcus leads directly out from its respective opening, and 

 would seem to answer the comb-like part in the gills of fishes. 



At the root of the tongue, nearly as far back as the openings reach, 

 the trachea begins, much in the same manner as in birds, turtle, toads, 

 &c. It passes backwards above* the heart, then divides into two 

 branches ; one going to each lobe of the lungs. 



The lungs are similar to those of the Tricoilia, being two long bags, 

 one on each side, which begin just behind the heart, and pass back 

 through the whole length of the abdomen, nearly as far as the anus. 

 They are largest in the middle, and honeycombed on the internal sur- 

 face through their whole length. The lungs at the hinder end are 

 loose, having no attachment ; at the fore-end they are attached by a 

 double membrane to the back and to the liver. 



The heart is of the Dicoilia [type] ; it is situated near the head, as in 

 fish, and is enclosed in a pericardium which almost fills the thorax, 

 makes a kind of diaphragm or distinct cavity between the fore-part and 

 the cavity of the belly, as in fish. It consists of one auricle and one 

 ventricle. 



The auricle does not consist of one regular bag, but is divided into 

 a number of processes or branches, which makes it very irregular both 

 on its external and internal surfaces : it almost encloses the ventricle, 



* To avoid confusion in our ideas, which might arise from the use of the words 

 'anterior,' 'posterior,' 'upper,' 'lower,' &c, in the whole of the description the 

 animal is considered as horizontal, and the head the fore-part, the back upwards. 



que cette communication des narines avec la bouche est pour lui le principal carac- 

 tere distinctif entre les reptiles et les poissons."] 



