118 
BULLETIN OF THE BUREAU OF FISHERIES 
The structure of the teeth, which has been relied on to separate the genera differs 
radically with the sex and also with age as follows. In the young below 25 millimeters 
in total length, the teeth are quite small, flattened, proximate, in a single row and 
their distal edges are apparently entire, at least so far as examination with a binocular 
microscope discloses. Between 25 and 30 millimeters in length the teeth in both 
sexes change to those having their distal margins distinctly notched. In the female 
the single row of notched, small, compressed and proximate teeth remains through- 
out life. In the male, however, a radical change in the character of the teeth takes 
place with age. When the young male reaches a length of between 35 and 40 milli- 
meters, two to four enlarged teeth begin to appear in the lower jaw behind the outer 
row of small teeth. In the larger males this second row of enlarged teeth number as 
high as 8, the usual number being 4 or 6. The outer row of teeth remains as in the 
female in specimen up to about 40 millimeters. After the fish exceeds that length 
they begin to change once more. The teeth become longer and more widely spaced, 
and their edges are entire. The larger, entire teeth first appear at the symphysis of 
the upper jaw and gradually spread sideways. The change is gradual; and some 
small bifid teeth, intercalated with the larger teeth, may be present in males as large 
as 72 millimeters, although they usually disappear at about 60 millimeters. In the 
lower jaw the change takes place later, between 55 and 60 millimeters in length. 
After 72 millimeters in length the teeth become pointed, fanglike as compared with 
that of the female, and rather widely spaced, so that when full-grown specimens are 
compared their widely different characters are quite striking. 
Not only have the males and females been placed in separate genera, but the 
young have been described in still another genus. As has been stated above, the very 
Figure l.—Evorthodus lyricus. 
Upper, mature male; lower, mature female. Drawn by Miss Louella E. Cable from speci- 
mens taken on the coasts of Louisiana and Texas 
