EDUARD UHLENHUTH 



537 



Fig. 5. 



Fig. 6. 



Figs. 5 to 10. In Ambystoma tigrinum the development of the yellowish 

 spots is more retarded at low temperature than metamorphosis, and the develop- 

 ment of the yellowish bands is completely inhibited. Fig. 6 photographed from 

 live specimen. Fig. 10 photographed from water color painting made from 

 preserved specimen. Rest of figures photographed from water color paintings 

 made from live specimens. Natural size. 



Fig. 5. Tigrinum 1917, 5 3. 25°C., 12 days aftei- metamorphosis. Numer- 

 ous small yellowish spots. 



Fig. 6. Tigrinum 1917, U 4. 15°C., 11 days after metamorphosis, larval 

 coloration. No spots. 



from one female. Furthermore, the difference in coloration as 

 observed here is not due to the influence of light but to the influence 

 of temperature. The action of the temperature is manifested in two 

 ways: first, in low temperature the development of the yellow spots 



