KEPTILES AND AMPHIBIA 173 



deliberate blows of his tail. Eusconi was not aware of the 

 method of depositing spermatophores which followed this 

 courtship. He also describes the male of another species, 

 apparently Molge jpalmata, as agitating his tail with great 

 rapidity in front of the female. Gasco's observations were 

 made at Genoa on Molge alpestris, which has a somewhat 

 narrow dorsal crest. He believes the vibration of the tail 

 by the male in front of the female is intended merely to 

 stimulate and excite his own sexual organs, and states that 

 the male never touches with his tail any part of the female. 

 Zeller describes the male as beating his own flanks with his 

 tail, and as performing, supported on his fore legs, a rapid 

 undulating movement of the body. It is this latter move- 

 ment which has caused, in my opinion, the development of 

 the dorsal crest on the body. A similar excrescence is 

 wanting on the belly, partly because the motion is more 

 active in the dorsal region, partly because the pressure of 

 the belly on the ground would prevent the formation of a 

 vertical membrane. Zeller states that these actions of the 

 male are continued usually for hours or even days with only 

 brief interruptions, and thus we see that the mechanical 

 forces at work have ample time to produce their effect. 

 It would probably be found, if the precise movements of 

 the different species were studied, that the degree of develop- 

 ment of the dorsal crest on the body corresponded to the 

 amount of lateral vibration in this part of the body. 



An excellent summary of what is known concerning the 

 courtship and fecundation of the Urodela is given by Dr. 

 Boulenger. 1 He points out that the male is " ornamented " 

 with more brilliant colours, and with dorsal and caudal crests, 

 or other temporary appendages, only in those species in which 

 no amplexus takes place, that is to say, in which the male 

 does not clasp or embrace the female. This might be con- 



1 Zool. Jahrb. systematik, Band vi., 1892, p. 447. 



