134 THE AMERICAN CHARACIDAE. 
fasciatus as an intermediate species. lLiitken separated the species with an 
incomplete lateral line as a variety, T. interrupta. Upon reéxamining Liitken’s 
specimens Eigenmann pronounces 7’. fasciatus and T. interrupta as being unques- 
tionably distinct, differing in several characters besides the completeness or 
incompleteness of the lateral line. 
During the examination of the very large series of specimens enumerated 
in the present work I found a complete lateral line in several species. Thus, 
among one hundred and two specimens of Hemigrammus levis from Lago do 
Maximo one had a complete lateral line. In over one hundred from other 
places the lateral line is incomplete. Of nineteen hundred and seventy-seven 
specimens of Hyphessobrycon gracilis from Brazil four have the lateral line 
complete. Of five specimens of H. inconstans two have the lateral line complete. 
Of nearly fifteen hundred specimens of H. liitkeni four have the lateral line 
complete and several others have it interrupted. Of one hundred and five 
specimens of H. inconstans from Quibdo, eighteen have a complete lateral line, 
eleven have it complete on one side and not on the other, and seventy-six have it 
incomplete on both sides. 
Hyphessobryeon is separated from Hemigrammus by the single charac- 
ter, the scaled or naked condition of the caudal. Three out of the present 
fifty-four species of the two genera seem to be intermediate in regard to this 
character.’ Thus, Hemigrammus elegans has but few scales on the caudal and 
is put with Hemigrammus because it lacks the enlarged scale at the base of 
each caudal lobe which is characteristic of Hyphessobrycon. 4H. analis usually 
has only four or five scales on the caudal, but like H. elegans it lacks the 
enlarged basal scales and is placed with Hemigrammus. Jd. stictus usually 
has the basal scale and is, therefore, put with Hyphessobrycon, although it 
sometimes has a number of small scales actually on the base of the caudal lobes. 
A question as to the validity of the species of these genera has been raised 
on the ground that these small fishes are immature, the young of other species. 
Accordingly dissections were made wherever sufficient specimens were at hand. 
One or more specimens were dissected of each of thirty-two species, and ovaries 
with large, in several cases apparently ripe, eggs were found in so many species 
that there is no room to doubt that, in most cases at least, we are dealing with 
mature specimens. The following table contains the result of the dissections 
in detail: 
