Siredon into Amblystoma, 365 
of the tail, and the color of the entire animal gradually as- 
only were partially altered, and at the present time, or nearly 
three weeks later, they still retain tubercular remnants of the 
external branchie, although in most other respects the change 
appears to be complete. The two remaining specimens, how- 
ever, which had throughout been kept with the three last, 
wed no distinct signs of changing, although the probability 
Of their doing so, and the importance of retaining some 
2 ble evidence of the original condition, led to the transfer of one 
