23 



British Batrachians. 



By G. A. BouLENGER, LL.D., D.Sc, F.E.S. 

 EemI December 12f//, 1919. 



I have been asked to tell you something to-night about our 

 Batrachians, a class of Vertebrates connecting the Fishes with the 

 Reptiles. They are poorly represented with us, but the few species 

 have always found favour in the aquarium and the terrarium, and 

 they lend themselves particularly well to observations on the life- 

 histories. Their breeding habits and their metamorphoses can be 

 easily observed in captivity and in a comparatively short time, thus 

 affording an excellent introduction to the study of Natural History, 

 whilst some of them are of constant use in the laboratory for 

 the first exercises in anatomy, as well as for experiments in 

 physiology. 



They are popularly known as Newts, Frogs, and Toads. 



The first of these belong to the order Caudata, or Urodeles, in 

 which the tail persists throughout life, and in which the meta- 

 morphoses are more gradual and far less striking than in the order 

 Ecaiidata, or Anures, embracing the two other types, which are 

 tailless in the perfect state, after having passed through the tadpole 

 condition, which is known to all of you. 



There are three species of Newts {Mohje or Triton) in the British 

 Isles, elegant creatures when in the water, which is their element 

 during the breeding season, lasting through spring and early 

 summer. The males then assume ornamental appendages in the 

 form of dorsal and caudal crests, or of membranes bordering the 

 toes, and with them m that condition it is very easy to distinguish 

 the species ; the females lack these appendages, and differ much 

 from the males in form, and sometimes also in coloration. 



The largest is the Crested Newt [Mohje cristata), growing to six 

 inches, of a dark grey or brown, often blackish colour above and 

 bright yellow or orange beneath, spotted or marbled with black. 

 The male's crest is very high, deeply serrated, and interrupted over 

 the lumbar region, and a silvery band adorns the side of the tail; 

 the female is distinguished by the absence of these characters and 

 by the presence of a yellow or orange streak along the lower edge 

 of the tail. 



Next comes the Common Newt {M. vnh/aris), up to four inches 

 long, of a paler brown, with dark brown or black markings, and 

 dark streaks along the head, the lateral of which passes through 

 the golden iris of the eye. The male's crest is also high, but unin- 



