REPRODUCTION 199 



unexplained reason, very seldom engaging in courtship when 

 in captivity. But a certain number of Tailed Batrachians are 

 known to spend a longer or shorter part of the breeding season 

 in sexual embrace ; for instance the land salamanders (Sala- 

 mandra), some American newts {Molge viridescens, M. torosa), 

 the Pleurodele newts of Spain and Algeria (Molge waltlii, M. 

 poireti), and the so-called Euprocti of the mountains of Southern 

 Europe (Molge aspera, M. montana, M. rusconii). The mode 

 of amplexus varies. 



In the following synopsis, the forms of which the mode of 

 reproduction is known are arranged according to their mode 

 of pairing. 



1. No amplexus, but a lengthy courtship in the water; 



male more brilliantly coloured than the female, and 

 ornamented with dorsal and caudal crests or other 

 temporary dermal appendages. — The true newts 

 (Molge cristata, M. vulgaris, etc.). 



2. Amplexus takes place ; no marked sexual differences of 



colour ; no dermal ornamental appendages. 



A. Amplexus of short duration and partly or en- 



tirely on land. — Salamandra, Salamandrina, 

 and probably all other viviparous or terrestrial 

 species, such as Spelerpes fuscus, Chioglossa, 

 Plethodon, and Autodax. 



B. Amplexus of more or less lengthy duration and 



in the water. 



a. The male, distinguished by a greater 



development of the fore limbs, clasps 

 the female in the axillary region 

 with the fore limbs. — Molge (Pleuro- 

 deles) waltlii, M. poireti, M. torosa. 



b. The male, distinguished by a greater 



development of the hind limbs, and 

 often by a prehensile tail, clasps the 

 female in the lumbar and caudal 

 regions. — Molge viridescens, M. (Eu- 

 proctus) rusconii, montana, aspera. 



This coincidence of courtship and sexual ornaments in the 

 male is highly suggestive of sexual selection. For in the forms 



