xlii 



affinity with them of the Batrachids, which were formerly combined with 

 them, is now universally conceded. The chief problem with regard to 

 them, therefore, is confined to the question as to the taxonomic value of 

 the characters distinguishing them from other forms. In consideration of 

 the isolation of the group, the saliency of the characters distinguishing 

 them, and the disturbance their intrusion among the Teleocephals would 

 induce, they are distinguished by ordinal rank. Their relations are most 

 intimate with the Batrachoid and Blennioid forms, and doubtless they have 

 descended from the same common progenitors 



GENETIC RELATIONS AND SEQUENCES. 



In further explanation respecting the relations of the various forms, it 

 may be remarked that immediate sequence does not by any means neces- 

 sarily imply immediate affinities. In view of the complex and manifold 

 relations existing, it is generally only possible in a linear arrangement to 

 indicate the nearest relations on one side. The most convenient mode of 

 arranging forms in a linear succession appears to be in series, — that is, 

 taking a number of types and arranging them successively, having regard 

 to the forms next most allied, till the series is exhausted ; and then recom- 

 mencing anew with that series whose first member is most nearly allied 

 to one of the preceding : — in other words, following a genealogical system 

 and assimilating it to a scheme, where we would have a given ancestor, 

 and then (1) eldest son, (la) eldest grandson, (16) eldest great-grandson, 

 etc. ; and after giving all terms of such lineage, we would recommence 

 with the (2) second son and proceed with his descendants in like manner. 



The arrangement to really express such relations or quasi-relations 

 would, however, demand a knowledge of fishes which no one now possesses, 

 and consequently no attempt has been made in this article to exhibit them; 

 frequently, indeed, the relations deemed most probable by the author 

 have been violated in deference to general opinion. But without going 

 into details, the following quasi-genealogical tree will convey the views 

 of the author respecting the relations of the major groups, the first table 

 exhibiting the relations of the more generalized orders, and the last of 

 the orders as well as suborders of the Teleost series. In all cases (except 

 the Vertebrates and Molluscoids), the branch to the left — major as well 

 as minor — indicates the supposed most generalized type of the two or 

 more springing or diverging from the same common stem : — 



The names printed in largest capitals indicate branches ; those in smaller, classes 

 and subclasses ; and those in smallest, orders ; whilst suborders are printed in lower 

 case. 



