36 Prof. Owen on Life and Species. 
stration of this principle, which I then satisfied myself was 
associated with and dominated by that of ‘adaptation to pur- 
pose,’ the step was plain—to me inevitable—to the conception 
of the operation of a secondary cause of the entire series of 
species, whether of plants, or vertebrates, or other groups of 
organisms, nh cause being the servant of predetermining in- 
telligen t 
But, side’ ‘derivation’ or ‘filiation,’ another principle in- 
fiuencing organization became recognizable in the course of 
studies and researches on Invertebrate animals, To this s prin- 
ciple, as more especially antagonistic to the theological idea, I 
gave the name of ‘irrelative repetition ; ;’ sometimes also, as it 
revailed | most in plants and zoophytes, of ‘ vegetative repeti- 
tion. ee The demonstrated constitution of the vertebrate endo- 
soak but ‘general’ and ‘serial’ homolo ” appeared to 
me to illustrate also the law of irrelative repetition. The re- | 
currence of similar segments in the spinal column and of simi- ~~ 
lar elements in a vertebral segment, struck me as analogous to 
the repetition of similar crystals as the result of noe force 
in the tings of an eae body. 
tes “ae of such gradual modifications were due from the 
fossil world :—‘ You ought,’ he said, ‘ to be able to show, e. g., 
the preaee ¢ forms between the Paleotherium and existing 
hoofed quadrupeds,’| 
‘They rogress of Paleontology since 1830 has brought to light 
progress 
gs missing links unknown to the founder of the science. 
own share in ‘the labor led me, after a few years’ research, 
: Cece: 
eeu po) (888) aod ok Profi 
§ oxut, lo 
{ “Gopendant ed peut Jour répondre, dans leur propre systéme, ae: “i les 3 espe- 
ies qu'entre la palmadliocesaree Aysentnhy d’a eee are — devroit découvrir 
quelque: Lome ernie, o gue jt ee est point arriyé,’— 
OXXxrx, tom. i, p. lvii. 
