248 



CLASSIFICATION OF FISHES. 



short anal, and some other characters of the Europeaii 

 sahuons, has the mouth completely vertical. It will be 

 seen that, throughout all the natural groups of ichthy- 

 ology, one type with the mouth opening vertically is 

 always to be found ; and this variation is so prevalent, 

 that whenever it is met with, we may be almost sure 

 it is the chironectiforra type of that circle of which, in 

 all other respects, it possesses the leading characters* 

 M. Cuvier has, therefore, very judiciously made the S. 

 anastomus of Linn. (^fig. 51.) the type of a genus distinct 



from that of Gasteropelicus, although he was not aware 

 of the reasons which induce us now to adopt it. In 

 all other respects but its narrowed head, and very small 

 vertical mouth, Anastomus has the general shape of 

 the true salmons ; the size, form, and relative propor- 

 tion of the fins being the same : it cannot be said, how- 

 ever to have the "■ form of the S. Thymallus," because 

 the first dorsal fin is not at all lengthened ; nor is it so 

 proportionably high as in that fish. We next come 

 to the sub-genus Mallotus, which has also the general 

 structure of Salmo, but with the remarkable character 

 (unique in this group) of rounded pectorals ; aU the 

 other salmons having these fins pointed. Only one species 

 of this singular type is known, — the Mallotus Groen- 

 landicus, or Greenland salmon, — which Bloch (pi. 381.) 

 describes as a small fish, mostly used as a bait for cods. 

 This type has the further pecuharity of the tail or caudal 

 fin not being symmetrical with the pectoral ; the latter 

 being rounded, whereas the former is forked ; while the 

 anal is more lengthened than in any of its congeners : 



