PEEFACE. 



In the First Edition the object of this ' Catalogue ' was stated to be 

 to give a description of the species of Tailless Batrachians in the 

 British Museum, with an indication of the history and origin of 

 all the specimens in that collection, and also an account of the 

 species which were known to exist in other museums but were desi- 

 derata in the National collection. This plan has been completely- 

 carried out in the present edition ; it contains descriptions of, or 

 references to, aU the species introduced into the literature, whilst 

 in the former edition no mention was made of species known from 

 imperfect descriptions onlj'. 



The rearrangement of this part of the zoological collections, 

 with a new Catalogue, had become very urgent for some time. By 

 the First Edition a fresh impulse to the study of Batrachians was 

 evidently given, many collectors turning their attention to them 

 and discovering a great number of new forms, so that the collec- 

 tion in the British Museum alone has been nearly tripled within 

 the last twenty years. That work fulfilled its purpose, but it has 

 also ceased to be a satisfactory guide in the examination and deter- 

 ' mination of these animals. Besides, the discovery of almost every 

 new generic type showed that the system proposed in the first 

 edition (complete as it was in itself) was artificial, and that the 

 employment of certain osteological characters, which had been worked 

 out by Cope, Mivart, and Parker, promised a much more natural 



\) 



