434 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



-i 1 1 r 



50 75 



STANDARD LENGTH IN MM 



Figure 12. — Comparison of the regression lines for the relation of snout length to standard length for five species ot 



Caranx. 



lower-limb to upper-limb gill rakers (fig. 2) 

 divides the seven species of Caranx into three 

 distinct taxonomic groups: (1) latus, hippo*, 

 bartholomaei, and lugubris; (2) crysos and dentex; 

 and (3) ruber. A general trend of a direct relation 

 between upper-limb and lower-limb gill rakers is 

 apparent, but this relation is not as sharply 

 defined as is the dorsal ray-anal ray relation. 



It is estimated from examination of many small 

 specimens that the full complement of gill rakers 

 for an individual fish will be formed by a size of 

 14 mm. Three of the species, bartholomaei, latus, 

 and hippos, exhibit a tendency for gill rakers at 

 the origins of both limbs to become smaller or 

 rudimentary with growth, but crysos and ruber 

 do not. 



Branch iostegals. — Branchiostegal rays were 

 counted on more than 300 specimens, representing 

 all species examined. Seven rays were found on 

 each side in all counts made — the number reported 

 as generally characteristic of the family. 



Scutes. — The estimated perimeters of the ranges 

 of the mean number of scutes evidence appreciable 

 overlapping in the individual species (fig. 13) ; hut 

 this character may be used for interspecific identi- 



fication. A few scutes have completed their indi- 

 vidual development on hippos and latus by 15.3 

 mm. and 16.1 mm., respectively. The smallest 

 size at which completely developed scutes'may be 

 present on these two species is unknown; probably 

 it is around 13.5 mm. The first scutes to complete 

 their development on the other three common 

 species do so between about 18 mm. and 24 mm. 

 As predicted by the perimeters, the range of the 

 mean number of scutes of crysos does not overlap 

 that of ruber or bartholomaei above 25 mm., and 

 does not overlap that of hippos above about 35 

 mm., and of latus above about 55 mm.; the range 

 of latus does not overlap that of ruber or bartholo- 

 maei and averages a greater number of scutes, 

 but it overlaps hippos at all sizes; the range of 

 hippos does not overlap that of ruber or bartho- 

 lomaei below about 25 mm., but does above this 

 size; and the. ranges of ruber and bartholomaei over- 

 lap at all sizes. The four specimens of dentex show 

 an overlap in this character with hippos, ruber, and 

 bartholomaei, but the true range for the species 

 may be below that of latus. An estimated range of 

 26 to 33 scutes for lugubris (from the specimen ex- 

 amined and published accounts) is similar to that 



