FISHES. 357 



concise description of a few of the next class, and re- 

 main with every sentiment of respect, 



Dear Sir, 



Your's, &c. 



LETTER LVI. 



" Thus the niail'd tortoise aiul the wand'ring ret, 

 Oft to the neighb'ring beach with silence steal." 



OPPIAN. 

 DEAR SIR, 



J HAVE already informed you that the third grand 

 division of fishes is that of the spinous, or bony kind. 

 These are obviously distinguished, by having a bony 

 covering to their gills; by being furnished with no 

 other instrument of respiration than gills; by their 

 .bones, which are sharp and thorny ; and by their tails, 

 which are placed in a situation perpendicular to the 

 body. 



The bones of this order of fishes are exceedingly 

 numerous and sharp pointed; and, as in quadrupeds, 

 so in these, they are the props or stays to which the 

 muscles, which move the different parts of the body, 

 are fixed. The history of any one of this order in its 

 general feature, includes that of all the rest. They 

 breathe air and water through the gills, and live by 

 rapine, each devouring such animals as it is able to 

 swallow. They propagate not like the cetaceous 

 tribes, which bring forth their young alive, nor by 

 distinct eggs, like most of the cartilaginous tribes, 

 but by spawn, producing hundreds of thousands at 

 one time. 



It is difficult to account for the different operations 

 of the same element upon animals that appear to 

 have the same conformation. To some fishes bred in 

 the sea, fresh water is immediate destruction; and, on 

 the other hand, some that live in our lakes and ponds 

 cannot bear the salt water. Philosophy may form 

 plausible hypotheses, but these can go no farther 

 than probability, nor claim any higher merit than 



