Review of Darwin’s Theory on the Origin of Species. 177 
tiods, say in the tertiary, and between that period and the pres- 
f one species, amt 
“a rous specimens exhibit differences which in his 
pinion entitle them to be distinguished into two, three, or more 
fain] It is plain, therefore, that whatever conclusions can be 
‘. ‘arene from the present animal and vegetable kingdoms 
or of a gradation of varieties into species, or into what 
xe of the American Academy of Arts and Sciences, iv, p. 178. 
SERIES, Vor. XXIX, No. 86.—MARCH, 1860. 
23 
