560 Studies in the Theory of Descent. 



of a dull white, made their appearance and these in 

 time increased in intensity. 



" When the Axolotl left the water on December 

 4th the gill-clefts were still open, but these closed 

 gradually, and after about eight days were over- 

 grown with skin and no longer to be seen. 



" Of the other larvae three appeared at the end 

 of November (i.e. at the same time when No. I. 

 came to the surface of the water) to have kept 

 pace in development with No. I., an indication 

 that for these also the right period had arrived for 

 accelerating the developmental processes. They 

 were therefore submitted to the same treatment as 

 No. I. No. II. became transformed at the same 

 time and exactly in the same manner as the latter ; 

 its gill-tufts were complete when it was first placed 

 in the shallow water, but after four days these had 

 almost entirely disappeared; in the course of about 

 ten days after it took to the land, the overgrowth 

 of skin on the gill-clefts and the complete assump- 

 tion of the salamander form occurred. During 

 this last period the creature took food, but only 

 when urged to do so. 



" In Nos. III. and IV. the development pro- 

 ceeded more slowly. Neither of these so frequently 

 sought the shallow spots, nor did they as a rule 

 remain so long exposed to the air, so that the 

 greater part of January had expired before they 

 took entirely to the land. Nevertheless the dessi- 

 cation of the gill-tufts did not take a longer time 



