DEVELOPMENT AND LIFE HISTORY OF SOME TELEOSTS 
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The anal rays are more retarded in development, and a full count is not yet obtainable. 
The pectoral fins remain short and rounded in both species. The ventral fins, though 
still lateral, are lower on the side and rather farther forward than in smaller fish, 
being inserted somewhat in advance of the base of pectorals, and the rays, of which 
three distinct ones of about equal length are present, reach well beyond the origin of 
the anal. 
In color the two species do not seem to differ, except for the black on the ventrals 
in chuss, which is missing in regius. The number of dark dots have increased some- 
what, though there is much variation among specimens. All specimens at hand of 
both species have black chromatophores on the head and back. Some specimens 
have black dots on the cheeks and opercles, some have a dark lateral stripe variable 
in length, and in others these markings are missing, apparently without regard to 
species. In the larger specimens of this group, dusky specks have begun to appear 
on the first dorsal (fig. 134). 
Specimens about 15 mm long.-— No pronounced changes in development have 
taken place since a length of 9.0 to 11 mm was attained in either species. However, 
the first dorsal is considerably higher and better developed, and the pectoral fins have 
become much longer, as shown in the accompanying illustrations. The caudal fin 
is quite variable in shape, for it may be rounded, straight, or slightly concave. The 
chin barbel first becomes evident in specimens of about this size. 
Figuke 13 i.—Urophycis chuss. From a specimen 9.5 mm long. 
The color is variable among specimens, some being more profusely spotted than 
others. In general, dark pigment has increased in both species. However, the only 
distinguishing feature in color noticed is the black on the distal part of the ventral 
in chuss, which is missing in regius, just as in much smaller specimens (figs. 135 and 136). 
The proportionate length and depth of the caudal portion of the body, which 
aided in separating smaller specimens of regius and chuss, are now so nearly the same 
that the distinction has vanished. 
The rays in the dorsal and anal, at least in some specimens, are not quite all 
formed. The development in 15-mm specimens, as in smaller ones, is rather more 
retarded in chuss than in regius. Some of the rays and fulcra remain difficult to see. 
However, with the use of comparatively high magnification and transmitted light, 
9-54 rays were counted in the dorsal and 54 or 55 in the anal in three specimens of 
chuss. In two specimens of regius 7-46 and 7-47 rays were counted in the dorsal, and 
44 and 47 in the anal. The counts, as shown in the key to the species, for adult 
chuss are — dorsal 9 to 11-56 to 61, anal 52 to 56; and for adult regius, dorsal 8 or 9-46 
to 51, anal 39 to 49. Therefore, the difference in the counts between the two species 
in 15-mm specimens is quite evident. 
