4 THE SALAMANDER 



I. Fecundation and Fertilization. 



One of the earliest writers to make observations on the develop- 

 ment of the Salamander was von Schreibers (1819 and 1833), who 

 correctly observed the method of deposition of the young, but was 

 mistaken as to the mode of impregnation of the female by the male 

 which he thought took place in water. Rusconi (1839) was the first 

 to observe the correct method of copulation, which normally takes 

 place on land, although he was quite at a loss to explain how 

 segmenting eggs came to be present in the oviducts before copulation 

 had taken place — a paradox which took many years to solve. 

 Rusconi's paper seems to have been overlooked by most subsequent 

 observers. The discovery of the receptaculum seminis in the female 

 by von Siebold (1858), although only indirectly concerned with 

 fecundation, nevertheless proved to be of great importance in 

 furnishing the ultimate explanation of the mystery which baffled 

 Rusconi. The next observer to discuss the mating of Salamanders 

 was Zeller (i 890-1), who confirmed the observations of von Siebold 

 that one act of coition apparently sufficed to fertilize more than one 

 batch of eggs. It was thought that the function of the receptaculum 

 seminis was to hold a reserve of sperms for future use, i.e. that it was 

 analogous to the receptaculum seminis of an insect. This view was 

 also supported by Paratre (1894). Zeller believed that copulation 

 took place at the time of deposition of the young because he found 

 that the receptacula of the females were then full, and he also found 

 spermatophores in the water with the larvae. Five years later 

 Schwalbe (1896) published a very careful and detailed account of 

 the life-history and development of the two European Salamanders, 

 prefaced by an equally clear and lucid review of the previous 

 observers. Schwalbe's account is the first really adequate statement 

 of the facts, which subsequent observers have confirmed, but to which 

 they have added only minor details. Schwalbe finds that locality and 

 external conditions have some influence on the actual times of deposi- 

 tion, copulation, &c., but that on the average fully developed em- 

 bryos are found in the oviducts of the females from May until June, 

 and then again in October and December. He also showed that 

 sperms may be found in the receptacula in May but not in June^ and 

 then again from July to November, copulation having taken place 

 during July. Thus he established the important fact that the sperms 

 must winter in the receptaculum seminis of the female. He also showed 

 that fertilization occurs high up in the oviducts. The key to the 

 mystery which Schwalbe has thus provided is that the sperms received 



