549 
past, has most likely been the active origin of the 
amblystoma race from the axolotl stock. Presumably 
the axolotl as the gill-bearing form is the primitive stock, 
the amblystomas being a derived race, but nevertheless 
representing a true species, of which the axolotl may be 
regarded as the larval form. The shrivelling of the gills, 
seen in the experiments on the axolotl, was probably due 
to a mechanical cause—that of dryness of the surroundings. 
Dr. Weismann, who believes that the axolotl is a de 
generate form, declares that the transformation of the 
axolotl into the amblystoma was not brought about by 
Natural Selection. 
“ If their gills by this means become shrivelled up or completely 
disappear, even this is not adaptation in the Darwinian sense, but the 
effect of directly-acting external influences and chiefly of diminished 
use.”—(Studies in the Theory of Descent, ft. jgi.) 
Mr. W. Mattieu Williams, speaking of the transforma 
tion of the Mexican axolotl into an amblystoma, says:— 
“ Here is a case of very rapid modification, in which the animal, 
without the aid of hereditary variation, without any destruction of the 
unfit and survival of the fittest, has at once adapted itself to varying 
external conditions—a case apparently supporting the old-fashioned 
development theories of the predecessors of Darwin.”—{Gentleman's 
Magazine, vol. cclxii., ft. 100.) 
(d) PALEONTOLOGY. 
“ Bones bear witness.” 
—Comedy of Errors. Act iv., sc. 4. 
It is the opinion of some writers that palaeontology does 
not afford any conclusive evidence of the action of Natural 
Selection. 
“ While the general testimony of palaeontology is overwhelmingly 
in favour of the view that some general law of evolution has operated