PREFACE. 



Dr, GihTTHEB dbseryes,-^'"' Tfiis volume concludes ^ he Order of Acan- 

 THOPTEKXGit as defined by Johannes Miiller. Weighty reasons have 

 been brought forwaKd against the natural limits of this Order, when 

 compared with the other coordinate -divisions of the Teleostbi; and 

 it would almost appear as if Miiller, in his attempt to base the 

 systematic distribution of that subclass on isolated anatomical 

 characters, had not been successful in creating one Order which 

 would comprise fishes allied in habit, in mode of Hfe, and in the rest 

 of their principal anatomical characters. But, frequent as are the 

 objections against MiiUer's modifications of Cuvier's system, no one 

 has proposed any arrangement which would give a more satisfactory 

 result, if put to the test of carrying it out to a detailed subdivision. 

 Systematic attempts not accompanied with, or confirmed by, proper 

 characters are unavailable to oihers, and may even delude the author 

 himself*. 



" Under these circumstances, I still feel satisfied to distribute the 

 fishes, on the base of Miiller's ordinal arrangement, into natural 

 minor divisions, whether called famiUes, groups, or genera; and, 

 in my opinion, there is no character equal in importance to that of 

 the structure and position of the fins ; for, as they are in immediate 

 connexion with the entire habit of the fishes and with their mode 

 of Hfe, they best indicate their natural afiinities, and, indeed, prove 

 to be the most constant and general characters. Isolated, striking 

 exceptions will occur, but they are comparatively few in number. 

 The examination of the skeletons has led to the conclusion that the 

 number of the vertebrae is another character of great importance for 

 the distinction of the families ; but whether it has any bearing of 



* For instance, I think it quite impossible for my highly esteeme-d friend, 

 Dr. V. Bleeker, to find one or several characters common to all the fishes of his 

 " Caterva 3. Blennii," without being obliged to take into the same division fishes 

 that are widely sundered from them according to his system. 



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