(1953) stated that these spines were not present 

 on a 208-mm. SL specimen. In the present large 

 series of western and eastern Atlantic sailfish, pte- 

 rotic spines are present only as traces on some fish 

 as short as 100 mm. SL, are present on all fish up 

 to 150 mm. SL, and are absent on specimens longer 

 than 150 mm. SL. Preopercular spines are present 

 on all specimens but the largest, 216 to 238 mm. 

 SL — they are probably lost at about this size. 



Scales 



Scale spines are first discernible on the dorsolat- 

 eral surface of the body on sailfish about 30 mm. 

 SL. Specimens about 50 mm. SL have spines on the 

 cheeks and most of the body, except for the area 

 on the side covered by the depressed pectoral fin 

 and on the back along the anterior portion of the 

 dorsal fin. Scales on the largest specimens, 216 to 

 238 mm. SL, are cycloid and differ from the illus- 

 tration and description of scales on a 101-mm. fish 

 (Gehringer, 1957) as follows : shape more elliptical 

 than round, spine relatively shorter and weaker, 

 and concentric ridges greater in number. On all 

 specimens longer than 30 mm. SL the spine tips 

 protrude through the skin and give a feeling of 

 roughness. 



Development of Caudal Keels 



Two keels on each side, extending from the base 

 of the caudal fin onto the caudal peduncle, develop 

 at about 84 to 92 mm. SL. The smallest sailfish 

 with keels is 83.8 mm. SL, and the largest without 

 keels is 91.4 mm. SL. The upper keel apparently 

 develops first as it is the only one present on the 

 few fish 85 to 90 mm. SL with but one keel. 



Development of Dorsal and Anal Fins 



As discussed under definitions of terms, the last 

 six or seven rays of both dorsal and anal fins form 

 distinct second fins in the adult. The dorsal and 

 the anal fins on all specimens in the present series 

 are single and continuous. On larger specimens the 

 few anal rays immediately forward of tiie terminal 

 six or seven rays are small and weak; these rays 

 are weak and overgrown with skin in the adult. 

 Dorsal rays in this relative position are not so 

 weak, but are less robust than those immediately 

 ahead or behind which do not become overgrown 

 with skin. On most specimens over SO mm. SL, 

 the distal portion of the anal ray immediately 

 ahead of the terminal six or seven ravs is de- 



pressed, overgrown with tissue, and nearly adnate 

 to the base of the succeeding ray. 



Pelvic Fin 



The first and second rays of the pelvic fin, which 

 in the adult are fused into one robust bony ray, 

 are nearly fused on the largest specimens, 216 to 

 238 mm. SL — the first ray appears as a short, tri- 

 angular-shaped segment of the leading edge of 

 the second ray. The third ray is separate and dis- 

 tinct at all sizes. 



PIGMENTATION 



Pigmentation of Atlantic sailfish larvae, juve- 

 niles, and adults has been described by several 

 authors, including Voss (1953), Gehringer (1957), 

 Robins and de Sylva (1963) , and de Sylva (1963) . 

 My comments here on pigmentation of fins and 

 body bars supplement these accounts for .speci- 

 mens 26 to 238 mm. SL and apply to both eastern 

 and western Atlantic specimens. 



Fins 



The pectoral fins are clear except for a few 

 melanophores at the bases of the first few rays 

 on the largest specimens. 



The pelvic fins are lemon-yellow with a few 

 melanophores on the membrane between the sec- 

 ond and third rays on sailfish over 155 mm. SL. 



Pigment on the anterior portion of the dorsal 

 fin is uniformly dusky to dark except for two to 

 several large, dark spots scattered in a nonuniform 

 pattern over the fin (figs. 1-5). On some fish the 

 first few dorsal rays are less densely pigmented 

 than the rest of the fin. Pigment extends posteri- 

 orly on the fin to the 34th to 40th ray — the last few 

 rays of the anterior portion have no pigment. The 

 posterior portion (terminal six or seven rays) of 

 the fin is clear except for pigment on the bases of 

 the fin rays and fin membrane on specimens longer 

 than about 135 mm. SL. 



The anal fin is clear on all specimens. 



The smallest sailfish with jiigment on the caudal 

 fin is 44.2 mm. SL; the largest without pigment on 

 the caudal fin is 51.7 mm. SL. A group of a few 

 melanophores is present on the lower lobe of the 

 caudal fin of a series of fish 44.2 to 60.0 mm. SL, 

 and a similar group of melanophores is also on the 

 upper lobe of a series of specimens 50.0 to 64.0 mm. 

 SL. The melanophores are coalesced into blotches 

 on several fish 53.2 to 67.0 mm. SL, and, though 



YOUNG OF ATLANTIC SAILFISH 



179 



