896 THE AMERICAN NATURALIST. [Vou XXXV. 
aborted. Besides loss of length, the opercula are gone and 
the external parts of the gill are reduced to mere warty lumps. 
On the floor of the mouth the tongue had not yet developed. 
The trunk region is also intermediate and presents both sire- 
don and salamander features. The coloration is still of the 
aquatic kind, showing no hint of the future dense black general 
tone spotted with irregular blotches of brilliant lemon yellow 
so characteristic of the land forms of the species. On the other 
hand, the dorsal fin is wholly absorbed, 
and the toes are no longer “ webbed"; 
instead, the skin fits closely and the toe 
is cylindrical and tapering. With this 
change of the toes and the fins the 
power of locomotion by swimming in 
water must be very considerably dimin- 
ished. The post-abdomen has also 
reached the final form, the tail fin being 
nearly completely absorbed. 
Fe ee cin Ne’ -legetmeier reports in 1870 his obser- 
showing the transition to the vations upon a transforming axolotl. His 
stem account is very brief. He says: “The 
specimens were hatched in the summer of 1868, and kept 
under similar conditions without any change having taken place 
beyond steady increase of growth during the succeeding winter 
and the summer of 1869. In the autumn one began to change; 
the external gills disappeared, the jaws became more pointed, 
and the skin assumed a singularly mottled appearance. The 
animal did not leave the water, but when the temperature was 
warm usually breathed by standing erect against the side of the 
aquarium and elevating the nostrils above the surface; during 
the cold weather it usually remained submerged, rising at inter 
vals to breathe.” This case of Tegetmeier’s seems to be like 
the Colorado specimen in that the metamorphosis took place 
while the animal still maintained its habits of aquatic life. 
Apparently the same may be said of the transformations reported 
on by Marsh (68), Dumeril (70), and Chauvin (75). 
We do not know the cause of the transformation 
siredon. In the St. Paul form of Amblystoma the animal first 
of the 
