LIFE IN TEFFE. 239 
the fish which carries its young in its mouth, grows daily 
more wonderful. This morning Mr. Agassiz 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 oilier the Scopelines and Clupeoids, 
all of which are essentially marine. These relations may be traced to the 
details of the genera ; Gasteropclecus, from the family of Thai-acmes, is the 
pendant of Pristigaster among the Clupeoids, as Chalcinus recalls Pellona. 
In the same way may Stomias and Chauliodus be compared to Cynodon and 
the like ; or Sudis and Osteoglossuni to Megalops, and Erythrinus to Ophiceph- 
alus, &c., &c. The Goniodonts may at first sight hardly seem 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 Pegasus, and 
further remember that to this day all the ichthyologists, with the sole excep- 
tion of C. Dumeril, have united Pegasus in one order with the Pipe-fishes, it 
will no longer be doubted that the Goniodonts have at least a remarkable anal- 
ogy with the Lophobranches, 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 Syngnathus, 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 Tctraodonts, the Flat- 
fishes (Pleuronectides), the Bill-fishes (Scomberesoces),- the Anchovis, Her- 
rings, and other forms of the family of Clupeoids, the Muromoids, the genu- 
ine Scuenoids, the Gobioids, &c., &c., they are chiefly known as marine types; 
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 Murrenoids, with which they have thus far been associated. The only 
real affinity I can trace in them is with the Mormyri of the Nile and Senegal, 
and with the Notopteri of the Sunda Islands. Eel-shaped fishes are by no 
means all related to one another, and their elongated form, with a variety of 
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 character 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. Among the Bivalve 
shells, it has long been known that the Amazons nourishes genera of Naiades 
peculiar to its waters, or only found besides in the other great rivers of South 
