264 LAMARCK, HIS LIFE AND WORK 
come obliterated, and that the more often nature 
leaves it at our disposal to establish distinctions only 
minute, and in some degree trivial peculiarities. 
“But some genera among animals and plants are of 
such an extent, from the number of species they con- 
tain, that the study and the determination of these 
species are now almost impossible. The species of 
these genera, arranged in series and placed together 
according to their natural relations, present, with 
those allied to them, differences so slight that they 
shade into each other; and because these species are 
in some degree confounded with one another they 
leave almost no means of determining, by expression 
in words, the small differences which distinguish them. 
“There are also those who have been fora long time, 
and strongly, occupied with the determination of the 
species, and who have consulted rich collections, who 
can understand up to what point species, among liv- 
ing bodies, merge one into another (foudcnt les unes 
dans les autres), and who have been able to convince 
themselves, in the regions (fartzes) where we see 
isolated species, that this is only because there are 
wanting other species which are more nearly related, 
and which we have not yet collected. 
“I do not mean to say by this that the existing 
animals form a very simple series, one everywhere 
equally graduated; but I say that they form a 
branching series, irrecularly graduated, and which 
has no discontinuity in its parts, or which at best has 
not always had, if it is true that it is to be found any- 
where (s'2/ est vrai qu'il sen trouve quelque part). It 
results from this that the species which terminates 
each branch of the general series holds a place at 
least on one side apart from the other allied species 
which intergrade with them. Behold this state of 
things, so well known, which Iam now compelled to 
demonstrate. 
“T have no need (desozv) of any hypothesis or any 
