2 ON THE SPECIES OF THE GENUS CHALCINUS. 
the short variety of O. angulatus that absence of the feat- 
ures mentioned would be rather unexpected, and if pres- 
ent, as I have no doubt they are, they should be placed 
amons: the generic characters. There are two series of 
intermaxillary teeth in young specimens. On the other 
hand, old specimens apparently have three more or less 
perfect series in the same region. This difference in in- 
dividuals of the same species is brought about somewhat 
as follows : the third tooth of the inner row on each side of 
the symphysis is crowded outward to take a position be- 
tween the two rows ; then, as the growth of the specimen 
continues, the first tooth on each side of the middle of the 
outer row is crowded inward, the third tooth of each sec- 
tion of this series afterward follows in the same direction, 
and still later the fifth tooth shows a disposition toward sim- 
ilar displacement, thus eventually producing what might be 
described as a triserial arrangement of the intermaxillary 
teeth. The amount of curvature from snout to tail, in the 
dorsal outline, as given in descriptions is to be taken with 
some allowance ; it varies greatly with the age and degree 
of plumpness of the individual and also changes in death 
and in alcohol. Including several varieties, the following 
species seem to be all that can be recognized at present. 
Scales from upper edge of gill opening to caudal 30-40 ; 
rays in the anal fin 24 (23) . . . O.pictus. 
rays in the anal fin 28-33 ; 
from dorsal to lateral line 6 scales ; 
lateral line of 32 scales . 0.2'>circinensis. 
lateral line of 33-40 scales (7. angulatus. 
from dorsal to lateral line 5 scales ; 
base of anal extending beneath that of dorsal ; 
form sh(H't and deep . G. guntheri. 
base of anal behind that of dorsal ; 
form elongate .... (7. alius. 
