440 
BULLETIN OF THE BUREAU OF FISHERIES 
spot — continued croaker — continued 
LENGTH, 0 MILLIMETERS 
Anal rays not definitely developed, the articula- 
tions between the rays and the interhaemal 
spines, however, are evident and, although a 
definite count generally can not be made, it is 
clearly evident that the anal base is a long one. 
Caudal fin imperfectly developed and short. 
Body at origin of anal quite slender in proportion 
to the anterior part of body. 
Vent usually more than an eye’s diameter in 
advance of anal. 
Eye large. 
Anal fin developed about as in the spot. Al- 
though a definite count usually can not be 
made, it is evident that the fin base is shorter 
than in the spot. 
Caudal fin somewhat better developed, longer, 
and more pointed. 
Body at origin of anal proportionately much 
deeper. 
Vent always less than an eye’s diameter in ad- 
vance of anal. 
Eye somewhat smaller. 
LENGTH, 10 MILLIMETERS 
Body at origin of anal comparatively slender, 
tapering gradually to caudal peduncle. 
Anal fin with II, 12 or 13 rays, the spines rather 
weak. 
Body at origin of anal deeper, tapering more 
abruptly to caudal peduncle. 
Anal fin with II, 7 or 8 rays, the spines, especially 
the second one, much larger and stronger. 
Caudal fin moderately long and round. Caudal fin longer and strongly pointed. 
Dorsal spines largely undeveloped; that is, they Dorsal spines better developed, with free points, 
are just beginning to appear and have no free 
points. 
Eye comparatively large, nearly as long as snout. Eye smaller, shorter than snout. 
Vertebrae 10 or 11 + 14 or 15. Vertebrae 8 to 10+15 or 16. 
The similarity of the young spot and croaker ( Leiostomus xanthurus and Micro- 
pogon undulatus ) on the one hand and the red and black drums ( Scisenops ocellatus 
and Pogonias cromis) on the other is pronounced and separation is difficult until a 
sufficient size (about 6 to 10 millimeters) is attained to admit the enumeration of the 
fin rays. Specimens less than 5 millimeters long of the red and black drums are not 
available for comparison. However, at a length of 5 millimeters the drums generally 
may be separated from both the spot and croaker by the presence of dark markings 
along the back which are entirely wanting in the spot and croaker of this size and for 
some time afterwards. According to Pearson (1929, pp. 139 and 158) the dark 
chromatophores appear on the upper parts of the body of both drums at an early 
age and, therefore, may be used, also, in identifying young less than 5 millimeters 
long of the species under consideration. Furthermore, at a length of about 3 milli- 
meters a rather definite row of dark chromatophores, about 3 to 7 in number, usually 
appears along the ventral edge of the tail (caudal peduncle after the anal fin is devel- 
oped) in the spot and croaker. These color markings seem to be missing in the drums. 
In specimens about 7 millimeters long and until pigmentation becomes general the 
drums are much more profusely spotted than the other two species. 
