PEOFESSOE FLOWEE ON THE EECENT ZIPHIOID WHALES. 205 



3, 5, 7, 9, 11, and 12, they differ from the typical Dolphins and agree with the 

 Cachalots ; and though they are separated from the latter by certain definite characters, 

 as Nos. 2 and 6, and others of less importance, there is no doubt that the group of 

 which Physeter is the type and that which includes Zij)hius and its immediate allies 

 are closely related, and should be considered subdivisions of one great division which 

 excludes all the other Odontocetes. Perhaps it is most convenient to treat them as 

 subfamilies of a common family Physeteridce, taking its name from the earliest charac- 

 terized genus Physeter (Linn.), and, according to the convenient nomenclature rules of 

 the British Association Committee, to call one PhyseterincB and the other Ziphiince^ ; 

 though some zoologists may prefer to raise both to the rank of families. 



Among the restricted Delphinidse no genus is known which appears to form any true 

 transition towards the Physeteridse ; but the strange and aberrant genera Platanista, 

 Inia, and Pontoporia, which cannot be placed in either of the two principal families of 

 the Odontocetes, and yet have scarcely sufficient common characters to constitute a 

 group apart, do in some few respects fill up the otherwise wide intermediate spaced 



The excessively confused synonymy of the genera and species of the Ziphiinse, as 

 thus defined, is a cause of great difficulty in writing about this group, and makes one 

 almost hesitate to enter upon the subject, lest in endeavouring to clear up the confusion 

 the perplexity should be inadvertently increased, either by adding new synonyms or by 

 adopting and perpetuating ill-chosen and incorrect terms. 



In a recent memoir on the group by Professor Owen^, the difficulty is disposed of 

 in a very summary manner by uniting all the known forms, both living and extinct 

 (with the exception of Hyperoodon), under the generic name of Ziphius. This pro- 

 ceeding at all events has the merit of running no risk of adding to the confusion 

 of nomenclature which has been caused by hasty or ill-defined generic subdivisions, 

 often founded on imperfect or fragmentary knowledge of the animal described. But, 

 however great our admiration may be for this strong-handed resistance to the system 

 of name-coining, which is fast rendering the study of zoology almost an impossibility, 

 it must not lead us to overlook well-marked structural characteristics by which certain 

 small groups of species are allied together and differentiated from others, whether we 

 call them genera or by any other term. The question now is, can the genus Ziphius, 

 as understood by Owen, be divided into any such groups ■? 



' This is the arrangement adopted in the sketch of the classification of the Cetacea given in Trans. Zool. Soo. 

 vol. vi. p. 113. 



' In the attempt at a natural classification of the Cetacea just referred to, I had provisionally grouped these 

 genera into a single family, between the Physeteridse and the Delphinidse : hut the details of the anatomy of 

 Pontoporia, first made known in the valuable monograph of Dr. Burmeister, published in the 'Anales del 

 Museo Publico de Buenos Aires,' vol. i. pp. 389-442 (1869), show that this family can scarcely be retained, 

 without at least considerable modification of the characters assigned to it. The only alternative seems to be to 

 make of each of these three genera a distinct family. 



' " British Fossil Cetacea from the Red Crag," Palaeontographical Society's vol. zxiii. (1870). 



2h2 



