284 



CLASSIFICATION OF FISHES. 



want a fifth to enable us to return again to the ancho- 

 vies, with which we began our survey. We should 

 suppose, from theory, that such a type should present 

 us with some of the characters of Nbtopterus, joined to 

 others which would be more characteristic of Engraulis, 

 and these so combined as to present a structure altogether 

 peculiar : this, we repeat, would be our theoretical notion 

 of such a type ; but is it only theoretic, or is there, in 

 reality, such a fish ? This question we can now positively 

 answer in the affirmative: the Engr. Hamiltonii of Mr. 

 Gray {fig. 5Q.) has precisely that union of character? 



which we have described; and although there is nothing as 

 yet to guide us but the figure*, we cannot but be struck 

 with the belief that it represents a form intermediate be- 

 tween Engraulis and Xotopterus : it has the head of the 

 former, the snout being considerably advanced beyond 

 the lower jaw ; while it has the long anal fin of the 

 latter, and this fin, moreover, is so united to the caudal, 

 that, like Xotopterus, it might have very well been 

 arranged, by the old authors, among the Gymnoti. Its 

 other characters are still more remarkable, and renders 

 it the most extraordinary fish in the entire family of 

 Clupeidcp. We have had, in fact, some hesitation in 

 placing it here, under a suspicion that, instead of being 

 a secondary form, as we now arrange it, among the 

 toothed herrings {Elops), it was, in reality, one of the 

 primary types of the whole sub-family. Nevertheless, it 

 has been our rule, in all such cases, to be guided in the 

 first instance by what appears the greatest affinity; and 

 under the impression that Trichosoma is more connected 

 to Engraulis than to any other of the herrings, we 

 * Gray, Ind. Zool. voL i. pi. 85. fig. 3., here reduced. 



