86 CALIFORNIA ACADEMY OF SCIENCES. [3D Ser., 



ison made possible between it and its eastern relative, I can- 

 not do better than to carry the comparison along as I pro- 

 ceed with the narration of my observations. To this end 

 it will be best to quote at the outset Gage's summary of his 

 own studies on D. viridescens. His paragraphs that will 

 concern us here are as follows: — 



"4. After the gills are absorbed the animal leaves the 

 water, and the color gradually changes from an olive-green 

 to brownish-red, and finally, during the same season, as- 

 sumes a bright yellowish-red, the vermillion spots remaining 

 and becoming partly surrounded by black pigment." 



"6. In the autumn of the third, or the spring of the 

 fourth year after hatching (when two and one-half or three 

 years old), the red changes for a viridescent coloration. 

 This may occur with or without entering the water. If the 

 water is entered the animal changes to an aquatic mode of 

 life." 



" 8. After becoming adult and transforming to the viri- 

 descent coloration, the Diemyctyhis always remains of that 

 general color, and never again becomes red, even when 

 kept out of water a whole year, thus showing that the color- 

 ation is dependent neither on food, season, nor environ- 

 ment, but is normal for a given period of life only." 



" 9. The adult viridescent forms are purely aquatic 

 under favorable conditions, and after once entering the 

 water do not leave it, although they are able to live for 

 several months, and perhaps indefinitely, in moist places, 

 wholly out of water." 



The changes of form and color in our species which take 

 place during metamorphosis from the larval state, I give in 

 detail in my description of the larva. On that point I need 

 consequently do no more here than refer to figs. 4, 5i 6 

 and 7. 



I have already shown that immediately after metamorphosis 

 the adults are more strictly aerial than at any other period 

 in their lives, and that at this time they possess the tuber- 

 culated skin and narrow tail in the fullest degree. I have 

 also given reasons for believing that the males, at least, 



