INTRODUCTION. 



I. Classification. 



For many years the Tailless Batrachians (Ecaudata 

 s. Anuha) were classified in a very unsatisfactory 

 manner. The genera Bufo and Hyla were, it is true, 

 always regarded as the types of distinct groups: but 

 Pelodytes, Pelobates, Discoglossus, Bombinator, and 

 Alytes were placed with Bana, or in separate families 

 in most unnatural associations. 



Dumeril and Bibeon, in the eighth volume of their 

 standard work, ' Erpetologie generale,' published 1841, 

 after dividing the order into two sub-orders, Phanero- 

 glosses and Phryna glosses (=■ Aglossa, the two exotic 

 genera Pipa and Xenopus), a primary division first 

 introduced by Wagler in 1830 and which has stood 

 the test of time, combined the Phaneroglossal genera 

 into three families — Raniformes, Hylaefovmes, Bufoni- 

 form.es ; the two latter containing each a single Euro- 

 pean genus, whilst under the former all others were 

 arranged in a series without further subdivision. 



So unnatural an arrangement evoked criticism from 

 all who were acquainted with the life-histories of the 

 European forms ; and an excellent French observer of 

 these animals, A. Thomas, in a paper published in the 

 'Annales des Sciences naturelles,' 1854, dwelt upon 

 the correlation which exists between the shape of the 

 pupil and the mode of amplexation duriug parturition, 

 and proposed to group together on the one hand those 

 genera that have a horizontal pupil and an axillary 

 embrace, on the other those that combine a vertical 

 or triangular pupil with a lumbar embrace. These 

 divisions were later provided with names by Beuch in 

 1863 (Plagloglena, Orthoglena), and by de l'Isle in 

 1877 (Alamplexes, Tngidnamplexes) . 



How exaggerated the importance attached to this 

 correlation, which, besides, holds good only for the 

 European forms, is now apparent to all. Yet the ar- 

 rangement proposed by Thomas was a decided advance 



