PERENNIBRANCHIATA. 383 



from South Carolina in America, to Europe, three of which I have seen, 

 and it is probable there are many more. The first of them that came 

 to Europe were brought to London in the year 1758 by Mr. Lake, who 

 had resided many years in that province. I bought his whole collec- 

 tion of things, in which were two different species of this genus ; and 

 since that time I have got a third. Some time after Dr. Garden, of 

 Charles Town, South Carolina, sent one of this species to the late Dr. 

 Linnaeus 1 , which he called the siren. 



To the eye, two of them may pass as different species of the same 

 genus ; but the third might be supposed to belong to a aother, to which, 

 however, it has but little connexion, being in its internal economy 

 closely connected to the above two. 



This tribe of animals is widely different from all hitherto known. 

 They are compounded of two grand divisions of the animal kingdom, 

 yet not so as for all their parts to partake equally of both ; for some 

 parts incline more to the one of these divisions, other parts to the other, 

 while a few are pretty distinctly made up of both, so as to be truly 

 double, just as the parts of generation are in perfect hermaphrodites; 

 and these parts are the organs of respiration, to which the circulation 

 must of course correspond. They hold with respect to respiration a 

 middle rank between fish, which breathe water, and those immediately 

 above them, which breathe air, viz. those called Amphibia 2 , and they 

 are placed in this respect between the two, filling up the scale. 



The manner of life and general economy of the animal determine 

 the structure of less important parts. 



These animals give the true idea of the Amphibia, while all those 

 others which have got this appellation do not in the least deserve the 

 name. This appeared to me long ago to be the case, and therefore I 

 supposed there was not properly any such animal as an amphibian ; 

 for because an animal can dive, and stay, or live a considerable time 

 under water, it is not to be reckoned a bit more amphibious than any 

 other animal, whose stay under water is shorter. The circumstance of 

 being terrestrial or aquatic depends entirely upon the medium in which 

 an animal respires. One of the Tetracoilia can live in water if you will 

 allow it to breathe air, but not otherwise ; and the cetaceous fish can 

 only stay under water between every inspiration and expiration, as is 

 proved by the whale, &c. ; and a fish can live out of water, if it is still 

 allowed to breathe water. The animals usually named Amphibia in like 

 manner can only keep under water during the interval between inspira- 

 tion and expiration; but as their times of respiration are much less 



1 [Linnaeus died in 1778.] 



2 [By Linnaeus, ' Systerna Naiime,' Ed. xii. 1766, vol. i. p. 19.] 



