POMPANOS OF SOUTH ATLANTIC COAST 



215 



spines near the upper end of the gill opening 

 (figs. 1-3). 



Trachinotus sp. — In the 3.07-niin. specimen, 

 the three primary margin spines are present, 

 superimposed by two spines of the prcopercular 

 face series. The 4.0- and 4.66-mm. fish have 

 three primary margin spines and three primary 

 face spines (figs. 1-3). 



T. carolinus. — At 7.2 mm. there are two spines 

 on the lower limb and one on the upper limb of 

 the margin series, plus the angle spines. Only 

 one face spine (PFS 3) is obvious, the other two 

 are virtually extinct (fig. 4). By 11 mm. there 

 are three spines on the lower limb and four on 

 the upper, plus the angle spines, in the margin 

 series. Two face spines (PFS 1 and 3) are pres- 

 ent but reduced (fig. 5). The face spines are 

 obliterated, and the margin spines reach their 

 ma.ximum numerical development at 12 to 13 mm. 

 By 18 to 20 mm. all but the primary margin 

 spines have become assimilated into the pre- 

 opercle. PMS 2 and 3 are not obvious after 

 about 24 mm. PMS 1 is the last to be assimilated , 

 usually at about 33 mm., but is sometimes dis- 

 cernible to about 45 mm., and occasionally the 

 very tip of this spine remains uncovered after 

 the prcopercular margin has grown past it. 



T. falcatus. — At 5.0 mm. the primary spines 

 and one lower limb secondary spine are found in 

 the margin series, and the face series is comprised 

 of three spines (fig. 8). By about 7 mm. there 

 are two spines on the upper limb and two on the 

 lower limb of the margin series, and three face 

 spines are present but receding (fig. 9). By 

 11 mm. there are two spines on the lower limb 

 and about five on the upper limb of the margin, 

 and the three face spines are relatively small. 

 In 13- to 20-mm. specimens, two or three spines 

 comprise the lower limb margin complement, 

 two to many spines are found on the upper limb, 

 and the face series has disappeared (fig. 10). 

 Preopcrcular encroachment and spine assimilation 

 are rapid beyond this size, and only the primary 

 spines are conspicuous between 20 and 30 mm. 

 By 30 to 32 mm. all spines are assimilated. 



T. glaucus. — At 7.8 mm. two spines are evident 

 on the upper limb and none on the lower limb 

 of the margin. Three distinct face spines are 

 present (fig. 14). At 11.8 mm. the face spines 

 have disappeared, and there are three margin 

 spines on the upper limb and two on the lower 



(fig. 15). At 14.6 mm. tiircc spines are present 

 on each limb of the margin (fig. 16). After about 

 23 mm., PMS 1 is the only spine remaining up- 

 covered. This spine is assimilated at about 

 28 to 35 mm. 



BRANCHIOSTEGAL RAYS 



Branchiostegal rays were counted on specimens 

 in which the opercular flap was flared outward, 

 thereby presenting well-spread braiicliiostegal 

 membranes. In some specimens tlie innermost 

 rays are very narrow and inconspicuous and arc 

 "floating" or unattached. 



Trachinotus sp. — The 3.07-mm. specimen has a 

 complement of 5 or 6 + 5 or 6; the 4.0- and 4.66-mm. 

 specimens have 7 + 7 branchiostegal rays. 



T. carolinus. — Rays, usually 7 + 7. Of 220 

 specimens examined, 195 had 7 + 7 branchiostegal 

 rays, 9 had 7+8, 9 had 8 + 7, 6 had 8 + 8, and 1 

 had 8 + 9 (table 5). 



T. falcatus.— Rajs, usually 8+8. Of 203 speci- 

 mens examined, 117 had 8 + 8 branchiostegal rays, 

 9 had 7 + 8, 23 had 8 + 7, 53 had 7 + 7, and 1 had 

 6+7 (table 6). 



T. glaucus. — Raj's, usually 8 + 8. Of 49 indi- 

 viduals examined, 44 had 8 + 8 branchiostegal 

 rays, 3 had 7 + 7, 1 had 7+8, and 1 had 8 + 7 



(table 7). 



DENTITION 



The following description of dentition in Trachi- 

 notus was obtained from specimens 20 to 60 mm. 

 in length, but applies to all sizes in which teeth 

 are evident. The teeth on the premaxillaries 

 and dentaries are small, rather slender, conical, 

 and recm"ved. An irregular, double row of 



Table 5. — Left and right branchiosleyal ray relation for 

 SSO specimens of Trachinotus carolinus 



[Upper numbers in blocks represent speciniens with the inilicateil combina- 

 tion; numbers in parentheses represent approximate percentage o( the 

 sample with that combination! 



