26 SUPPLEMENT ON 



marvellous powers of the microscope, up to whales and 

 cachalots, surpassing twenty fold the largest terrestrial ani- 

 mals. There also we discover more particularly those grand 

 combinations of organs on which naturalists have founded 

 the distinction of classes : or to speak more correctly ; the 

 sea contains representatives of all the classes. For if we look 

 to the class of birds, so essentially aerial in their nature, we 

 find nevertheless that the penguins are by their structure 

 imperatively attached to the waves of the ocean. If we turn 

 to the mammiferous class we equally notice species and whole 

 genera devoted to the waters, such for instance are seals, 

 morses, and manatis, who are not formed to forsake the sea, 

 and the whole of the whale tribe, (cetacea) who can not even 

 quit the liquid element, notwithstanding that their respiration 

 compels them incessantly to rise to the surface. Reptiles are 

 represented in the waters by tortoises, (chelonians), crocodiles, 

 serpents, and in particular by the whole family of batrachians. 

 Insects are, in great numbers, aquatic even in their perfect 

 state, and a greater number still, do not rise into the air, to 

 reproduce their species and expire, until after they have 

 passed a much more considerable part of their lives beneath 

 the waters in the state of larvae and nymphs. Finally, in that 

 element we look for almost all the rnolluscae, the annelides, 

 Crustacea, and zoophytes ; four classes, which, upon dry land, 

 barely offer a few isolated representatives. Hence the 

 ancients considered, and it is the remark of Pliny in par- 

 ticular, that " Quicquid nascatur in parte naturae ulla, et in 

 mari esse ; praeterque multa quae nusquam alibi." 4. ix. 

 c. 11. 



But amongst the innumerable creatures which people and 

 vivify the vast extent of the liquid element, none predominate 

 so much, none are so exclusively confined to water, nor so 

 much the object of our notice, for the variety of their forms, 

 the brilliancy of their colours, and still more for the endless 



13 



