LIFE IX JEFF?!. 239 



tlie fish which carries its young in its mouth, grows daily 

 more wonderful. This morning Mr. Aga^siz was off before 



Characincs and Salmonides, based solely upon the presence of an adipose 

 fin, we may at once perceive how manifold are the affinities between the 

 Characines on one hand, and on the other the Scopelincs and Clupeoids, 

 all of which are essentially marine. These relations may be traced to the 

 details of the genera ; Gasteropelecns, from the family of Characines, is the 

 pendant of Pristigaster among the Chi)" nji!-. afi Chalcinna recalls Pellona. 

 In the same way may Stomias and Chauliodus he compared to Cynodon and 

 the like ; or Sudis and OsteotJo^ um to Mr-galops, and Krythrinus to Ophiceph- 

 altis, &c., c. The Goniodonts may at first sight hardly si-em to have any 

 kindred among marine fishes; but if we take into account the affinity which 

 unquestionably links the genus Loricaria and its allies with Peg ms, and 

 further remember that to this day all the ichthyologists, with the sole excep- 

 tion of C. Dume'ril, have united P _ isns in one order with the Pipe-fishes, it 

 will no longer be doubted that the Goniudonts have at least a remarkable anal- 

 ogy with the Lophobranchcs, if they should not be considered as bearing a close 

 structural relation to them. But this relation truly exists. The extraordinary 

 mode of rearing their young, which characterizes the various representatives of 

 the old genus Syngnathu>, is only matched by the equally curious incubation 

 of the eggs in Loricaria. And as to the other families represented in the basin 

 of the Amazons, such as the Skates, the Sharks, the Tetraodonts, the Flat- 

 fi-hes (Pleuroneetides), the Bill-fishes (Scomberesoces), the Anchovis, Her- 

 rings, and other forms of the family of Clupeoids, the Muraenoids, the genu- 

 ine Sckcnoi'ls the Gobioids, &c., &c., they are chiefly known as marine tyj 

 while the Cyprinodonts occur elsewhere both in salt and fresh water. The 

 Gymnotines are thus far only known as fresh-water fishes, nor do I see any 

 ground for comparing them to any marine type. They cannot be compared 

 to the Muroenoids, with which thev have thus far been associated. The onlv 



* 



real affinity I can trace in them is with the Mormyri of the Nile and Senegal, 

 and with the Xotopteri of the Sunda Islands. Eel-shaped fishes are by no 

 means all related to one another, and their elongated form, with a variety of 



g 



patterns is no indication of their relationship. It may, nevertheless, be in- 

 ferred from what precedes, that the fishes of the Amazons have, as a whole, a 

 marine diameter peculiarly their own, and not at all to be met with among 

 the inhabitants of the other great rivers of the world. 



These peculiarities extend to other classes besides fishes. Ainon-j the Bivalve 

 shells, it }MN lon^ b-en known that the Ama/ons nourishes genera of Naia 

 peculiar to its waters, or only found besides in the Other great rivers of South 



