112 



CHAP. VI. 



General Olsenations and Reflections, 



As 



to the number of animals, the species of 

 beasls, including also serpents, are not ery numerous. 

 Such as are ceuaiuly known and clearly described, 

 are not above a hundred arid-fifty. And yet proba- 

 bly not many that are oi" any considerable bigness, 

 have escaped the notice of the curious. 



The species of birds, known and described, are near 

 five hundred, ajid the species of fishes, secluding shell- 

 fish ? as many : but if the shell- fish are taken in above 

 six times the number. How many of each genus 

 remain undiscovered, we cannot very nearly conjee, 

 lure. But we may suppose the whole sum of beasts 

 and birds to exceed bv a third part, and fishes by 

 one half, those that are known. 



The insects, taking in the exsangiiious, both ter- 

 restrial andaquatic, may for number vie even with plants 

 themselves. The exsanguious alone, by what Dr. 

 Lister has observed and delineated, we may conjec- 

 ture cannot be less (if not many more) than three 

 thousand species. Indeed this computation seems to 

 be miu h too low : for it there are a thousand species 

 in this island and the sea near it ; and if the same 

 proportion hold between the insects native of Eng- 

 land, and those of the rest of the world (about a 

 tenth :) the species of insects on the whole lobe ; will 

 amount to ten thousand. 



