xX PREFACE. 
Date. Author. Genera. Names not previously used. 
1817 Cuvier 280 49 
1820 Temminck 201 29 
1826 Boie 343 30 
1831 Lesson 470 112 
. Pr. Bonaparte 561 28 
1837 Swainson 623 239 
Having thus exhibited the ratio of the increase of the generic 
names, I may now notice the gradual development of the number 
of species as given by some of the principal authors of systematic 
works, &c. 
Date. Author. Species. 
P75 Linnzeus i: sf 
1758 Sirota igh 
1766 miele 947 
1790 Latham 2951 
1823 Vieillot 3828 
1831 Pr. Bonaparte 4099 
In the foregoing remarks I have briefly explained the changes 
which have taken place with regard to the number of genera and 
species. I have also shown that Linneus himself considered it ne- 
cessary to establish other genera as he either became acquainted 
with additional species, or better acquainted with those previously 
known. What might have been the number of his genera had he 
acquired the knowledge of the vast number of species which are 
now known, it is not easy to conjecture, except by taking his ratio 
of species to genera in comparison with those now given by authors. 
For example, he had in his last edition 947 species divided into 104 
genera, so that there were about 9 species to each genus. There 
are now known and acknowledged by Naturalists about 6000 species ; 
if we divide these into 800 genera (for, as I have elsewhere ex- 
plained, I do not admit as established all the genera that are given 
in this work), it will give to each genus an average of 73 species, 
which is not much under the number given by Linneus. And I 
must also remark, that Linnzus knew little or nothing of the habits 
and ceconomy of the greater number of the species which he de- 
