94 PROCEEDINGS OF THE ACADEMY OF [1893. 



up to the vertebral axis, so that, morphologically speaking, there 

 are parts of two distinct axes, or individuals, present in each speci- 

 men. This evidence, together with that respecting the defective 

 development of the dorsal, and the tendency toward a hunch- 

 backed and deformed condition, perfectly parallel to the conditions 

 seen in traumatically deformed trout, seems to me to almost conclu- 

 sively prove that the double-tailed races of Gold-carp have arisen 

 in the first place as a consequence of injuries inflicted during the 

 early development of the eggs and embryos, and that the effects of 

 these embryonic traumatisms have become hereditarily transmissible, 

 as the facts seem to indicate. 



