220 A JOURNEY IN BRAZIL. 
Mr. Agassiz has already secured quite a number of the 
singular type of Acara, which carries its young in its mouth, 
affected by it, because no one would have appreciated more than he the 
results of my journey, which I had hoped soon to share with him. You 
will naturally understand that it is to the class of fishes I consecrate the 
better part of my time, and my harvest exceeds all my anticipations. You 
will judge of it by a few statements. 
On reaching Manaos, at the junction of the Rio Negro and the Amazons, 
I had already collected more than three hundred species of fishes, half of 
which have been painted from life, that is, from the fish swimming in a 
large glass tank before my artist. I am often pained to see how carelessly 
colored plates of these animals have been published. Not only have we tripled 
the number of species, but I count new genera by dozens, and I have five or 
six new families for the Amazons, and one allied to the Gobioidcs entirely 
new to Ichthyology. Among the small species especially I have found nov- 
elties. I have Characines of five or six centimetres and less, adorned with 
the most beautiful tints, Cyprinodonts resembling a little those of Cuba and 
the United S'tates, Scomberesoces allied to the Belone of the Mediterranean, 
a considerable number of Carapoides, and Rays of different genera from those 
of the ocean, and therefore not species which ascend the river; and a crowd 
of Goniodonts and Chromides of unpublished genera and species. But what 
I appreciate most highly is the facility I have for studying the changes which 
all these fishes undergo with age and the differences of sex among them ; which 
are often very considerable. Thus I have observed a species of Geophagus in 
which the male has a very conspicuous protuberance on the forehead, wholly 
wanting in the female and the young. This same fish has a most extraordi- 
nary mode of reproduction. The eggs pass, I know not how, into the mouth, 
the bottom of which is lined by them, between the inner appendages of the 
branchial arches, and especially into a pouch, formed by the upper pharyngials, 
which they completely fill. There they are hatched, and the little ones, freed 
from the egg-case, are developed until they are in a condition to provide for 
their own existence. I do not yet know how long this continues ; but I have 
already met with specimens whose young had no longer any vitelline sac, but 
were still harbored by the pi-ogenitor. As I shall still pass a month at Teffe' 
I hope to be able to complete this observation. The examination of the struc- 
ture of a great number of Chromides has led me to perceive the affinities be- 
tween these fishes and several other families with which we have never thought 
of associating them. In the first place, I have convinced myself that the Chro- 
mides, formerly scattered among the Labroides and the Sciasnoides, really con- 
stitute a natural group recognized nearly at the same time and in an iiidepen- 
