312 TIIE DOCTRINE OF DESCENT. 
rerum ex omni specie viventium unicum sexus par fuisse creatum, 
suadet ratio.” 
‘Ib. Non multum a veritate me aberratum confido, si dixerim, 
omnem continentem terram fuisse in infantia mundi aquis sub- 
mersam et vasto oceano obtectam, preter unicam in immenso 
hoc pelago insulam, in qua commode habitaverint animalia omnia 
et vegetabilia leete germinaverint.” 
6 Tot numeramus species, quot ab initio creavit infinitum ens.” 
Geoffroy St. Hilaire wrote to Cuvier: ‘ Venez jouer parmi 
nous le réle de Linné, d’un autre législateur de Vhistoire naturelle.” 
8 Ossements fossiles. 
19 L. Agassiz, An Essay on Classification, 1859. P. 253:— 
“As representatives of Species, individual animals bear the 
closest relations to one another ; they exhibit definite relations also 
to the surrounding element, and their existence is limited within a 
definite period. Ne 
As representatives of Genera these same individuals have a 
definite and specific ultimate structure, identical with that of the 
representatives of other species,” etc. See also P. 261 :— 
“ Branches or types are characterized by the plan of their struc- 
ture; 
“ Classes, by the manner in which that plan is executed, as far 
as ways and means are concerned ; 
“ Orders, by the degrees of complication of that structure; 
“ Families, by their form, as far as determined by structure ; 
“ Genera, by the details of the execution in special parts; and, 
“ Species, by the relations of individuals to one another, and to 
the world in which they live, as well as by the proportions of their 
parts, their ornamentation,” etc. 
20 Haeckel, Generelle Morphologie der Organismen (Berlin, 1866). 
II. 323, &c. 
21 Vespéce est—la réunion des individus descendant Tun de 
Yautre et des parents communs, et de ceux qui leur ressemblent 
autant qu’ils se ressemblent entr’eux.” Cuvier, Le Régne Animal, 
* OQ, Schmidt, Die Spongien der Kiiste von Algier, 1868, and 
Versuch einer Spongienfauna des atlantischen Gebietes, 1870. 
23 Haeckel, Die Kalkschwimme. Eine Monographie in Zwei 
Banden, Text und einem Atlas mit 60 Tafeln Abbildungen (Berlin, 
1872). 
