INHERITANCE OF ACQUIRED CHARACTERS. 443 



so dark as their parents. Standfuss and Weissman found that 

 Vanessa urticce behaved in a similar way. 



It is possible to bring these results into line with those of 

 Tower, if we assume that in Lepidoptera the germ-plasm can be 

 influenced even in the pupal stage, but. the action on the germ- 

 cell in this case does not influence the colour of the adult 

 so much as the action on the pupa. We cannot, therefore, 

 claim these investigations as a proof of the inheritance of 

 acquired characters. 



It is quite different, however, with the work of P. Kammerer 

 on Salamanders and on Alytes, the results of which have been 

 published in the ' Archiv. fur Entwickelungs-Mechanik,' Bd. xvii. 

 (1904), Bd. xxv. (1907), and Bd. xxviii. (1909). I propose, 

 therefore, to give a longer account of Kammerer's work, especi- 

 ally as, so far as I am aware, no such account has appeared in 

 English up to the present time. 



Two species of Salamander occur in Central Europe. The 

 ordinary lowland Salamander is the Spotted Salamander {S. 

 maculosa), whilst in mountainous regions it is replaced by the 

 Black Salamander (S. atra). 



The Spotted Salamander is black, with irregular large yellow 

 markings on the back and limbs. This combination of yellow 

 and black is a typical warning coloration, and indicates that the 

 animal is poisonous. The female carries the eggs in her uterus 

 for ten months, and in May enters the water, generally at night, 

 and gives birth to from a few to fifty young, fifteen being about 

 the average number. The young are surrounded by the egg- 

 membrane, which either bursts before or shortly after expulsion. 

 The new-born Salamanders have three pairs of long external 

 gills, a long tail furnished with a broad dorsal and ventral fin, 

 and four limbs, although these are small. The total length is 

 about 25 mm. or 1 in. Their general colour is blackish, with a 

 metallic golden and greenish lustre. They are very active, and 

 at once eat dead or living animal matter. During the first six 

 or eight weeks they assume a row of dark spots on the sides ; 

 these spots enlarge, and the whole skin becomes darker. Yellow 

 spots appear next, first above the eyes and on the thighs, later 

 upon the back ; the ground colour at the same time becomes 

 black. The metamorphosis is very gradual ; the tail-fin 



2m2 



