ESOCINiE, OR PIKES. 2^3 



at first imagined this was analogical^ because both have 

 the dorsal and anal fins very close to the caudal^ and some 

 of these fins, in Osteoglossum, are actually united ; but 

 then the great breadth and depression of the head in 

 Sudis is so directly opposed to the narrowness and com- 

 pression of this part in Osteoglossum, that we incline 

 more at present to assimilate the latter to Xiphostoma, 

 and the former to Chirocentrus. The question^ how- 

 ever, may be left open to discussion, because, at present, 

 Sudis is such an isolated form, notwithstanding its ge- 

 neral similarity to Erythrinus, that its other affinities re- 

 main uncertain. The analogy of Odontognathus to Ster- 

 noptyoc is more satisfactory ; and will equally hold good, 

 whether it be ultimately retained as a primary type of the 

 Clupeincs, or as one subordinate to Pristogaster. These 

 three last analogies, it must be remembered, regard 

 aberrant types ; and such types are always more varied — 

 more disconnected, as it were, among themselves — and 

 therefore more difficult to determine by a graduating 

 series of connecting species, than either typical or sub- 

 typical groups, wherein the intermediate modifications of 

 form are always more numerous. 



(247.) The EsociN^, or pikes, succeed the herrings : 

 they constitute, in our present arrangement, a sub- 

 family ; and although, in point of numbers, they appear 

 much more restricted than either of the three families we 

 have already disposed of, the variations in their structure 

 are so remarkable, and the gradations between them so 

 few, that their natural arrangement is proportionably as 

 difficult, and an artificial one is easy. Where the line 

 of continuity is lost or not discovered, the different forms 

 will appear isolated, and will then furnish the most po- 

 sitive characters ; but when these forms are modified in 

 a variety of ways, so as to present ramifications of dif- 

 ferent relations, we have some clue to the natural series. 

 The most prevalent character of all the fishes that have 

 been classed among the pikes, is that of the dorsal fin being 

 placed very far backward, so as to be close to the caudal ; 

 while the anal fin is immediately below it. The unusual 



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