630 Studies in the Theory of Descent. 



is drained, the fishermen stretch large nets across 

 the exit channels, and in these they not only find 

 ordinary Axolotls, but also some "sin aretes," 

 which they also designate " mochos," i. e. hornless 

 Axolotls, because they have no gills, but have 

 already reached the Amblystoma stage. Our 

 land-salamanders live in the water only as larvae, 

 but they also love and require moisture. Only the 

 female enters the water when she wants to deposit 

 her young (eggs with mature larvae), and then only 

 at the margin of shallow pools or small brooks. 

 The Mexican Amblystoma thus much more re- 

 sembles in its habits our water -salamanders 



ture may be a factor in some way concerned in these interest- 

 ing cases of transformation, and would in any case be well 

 worthy of experimental investigation. Some further details 

 concerning the Siredon Lichenoides of Lake Como have been 

 recently published by Mr. W. E. Carlin (Proc. U.S. National 

 Museum, June, 1881). The lake, which is shallow, is fed by 

 a constant stream of fresh water, but the water of the lake is 

 intensely saline. The Siredon never enter the fresh water 

 stream, but congregate in large numbers in the alkaline waters 

 of the lake. " When about one hundred and fifty were placed 

 in fresh water they seemed to suffer no inconvenience, but it 

 had a remarkable effect in hastening their metamorphosis into 

 the Amblystoma form. Of an equal number kept in fresh 

 water and in the lake water, quite a change occurred with the 

 former after twenty-four hours, while the latter showed no 

 change after several days of captivity. Those that were kept 

 well fed in jars usually began to show a slight change in from 

 two to three weeks, and all of them completed the change into 

 the Amblystoma inside of six weeks, while in some kept, but 

 not specially fed, there were but three changes in three 

 months." (Nature, Aug. 25th, 1881, p. 388). R.M.] 



