264 
PACIFIC SCIENCE, Vol. II, October, 1948 
Fig. 2. Juvenile Euthynnus lineatus; photographed against a white background to illustrate pigmentation of 
dorsal fin. 
cannot be counted accurately in unstained in¬ 
dividuals because of the small size of the most 
inferior rays. The dorsal fin has 15 spines in 
six specimens examined and 14 in a seventh, 
the first or second anterior spines, which are 
of nearly equal length, being the longest and 
the remaining spines decreasing in length rapid¬ 
ly and successively. The first dorsal reaches 
almost to the insertion of the second. The sec¬ 
ond dorsal fin rays, counted in 5 specimens, are 
12 in number, and there are in each case 8 dorsal 
finlets. The anal fin has 11 or 12 rays, and there 
are 7 anal finlets. The rays of the second dorsal 
and anal are difficult to count except in stained 
material because of the shortness of the first one 
or two rays. The finlets are connected to each 
other and to the fin by a thin membrane which 
extends less and less far toward the tips of the 
finlets as the fish grow until in the largest speci¬ 
men of 86 mm. it is only a vestige between the 
bases of the finlets. 
The gill rakers of our smallest specimens are 
very tiny projections on the gill arches and 
are difficult to count accurately. On such a 
specimen, of 32 mm. total length, they were 
counted on the first gill arch as 7 + 20. As the 
