pterotic and main preopercular spine lengths are 

 as defined by Gehringer (1957). Trvnik length is 

 the distance between the posteriormost margin of 

 the orbit and anterior point of emergence of the 

 upper keel on the caudal peduncle on specimens 

 85 mm. SL or longer (de Sylva, 1957). On speci- 

 mens smaller than about 85 mm. SL, which lack 

 keels, the posterior point for this measurement is 

 the insertion of the leading edge of the finfold of 

 the dorsal lobe of the caudal fin. This point is 

 directly above the anterior edge of the caudal keel 

 on larger specimens. Body length is the distance 

 between the tip of the mandible and the tips of 

 the midcaudal fin rays (Rivas, 1956). Body depth 

 is a vertical measurement at the insertion of the 

 first pelvic fin i-ay. Pelvic fin to anal fin is the dis- 

 tance between the insertion of the first pelvic fin 

 ray and the insertion of the first anal fin ray. 



Fin Rays 



The dorsal and anal fins are single fins in the 

 larval and juvenile stages, but in the adult the 

 terminal six or seven rays of both fins are sepa- 

 rated from anterior portions of these fins to form 

 second dorsal and anal fins. The fins are not 

 divided in the largest specimens in this study, 216 

 to 238 mm. SL, although the anal fin is nearly 

 divided. Even on my smallest western Atlantic 

 specimen (26.1 mm. SL), the shape and size of 

 the terminal six or seven rays distinguish them 

 from the few, less robust, more widely spaced rays 

 immediately ahead of them (which are overgrown 

 with tissue in the adult). I recorded ray counts 

 separately for the anterior and po.sterior j^ortions 

 of both dorsal and anal fins. The terminal ray in 

 the dorsal and anal fins though divided to its base, 

 is recorded as one ray. 



STUDY MATERIAL 



Western Atlantic specimens are from Silver Bay 

 cruises, all taken by dip net at the surface, under 

 a nightlight: Sta. 2139: 29°55' N., 80°38' W. 

 (about 35 nautical miles E. of St. Augustine, 

 Fla.) ; 2045-2245 hours, June 12, 1960; 33 m., sur- 

 face temperature 25.6° C; 3 specimens, 81.9 to 

 155 mm. SL. Sta. 2172: 35°00' N., 75°19' W. 

 (about 20 nautical miles SE. of Cape Hatteras, 

 N.C.) ; 2200-0250 hours, July 18-19, 1960; 146 to 

 366 m., surface temperature 27.3° C. ; 10 sj^eci- 

 mens, 67.1 to 216 mm. SL. Sta. 2201: 34°34' N., 

 75°40' W. (about 50 nautical miles E. of Cape 



Lookout, N.C.) ; 0030-0400 hours, July 24, 1960; 

 146 to 165 m., surface temperature 28.9° C; 135 

 specimens, 26.1 to 167 mm. SL. Sta. 2268: 

 32°36' N., 78°30' W. (about 70 nautical miles E. of 

 Charleston, S.C.) ; 0115-0300 hours, July 29, 1960; 

 190 to 198 m., surface temperature 28.9° C. ; 4 speci- 

 mens, 37.1 to 91.1 mm. SL. Sta. 4326:28°32' N., 

 80°03' W. (about 25 nautical miles E. of Cape 

 Kennedy, Fla.) ; 2310-0115 hours, September 3^, 

 1962; 70 m., surface temperature 27.8° C. ; 1 speci- 

 men, 137 mm. SL. Sta. 4403: 28°56' N., 80°25' W. 

 (about 30 nautical miles N. of Cape Kennedy, 

 Fla.) ; 2345-0145 hours, October 4-5, 1962; 24 m., 

 surface temperature 28.9° C. ; 1 specimen, 169 mm. 

 SL. 



Eastern Atlantic specimens are from Undaunted 

 Cruise 6801, all taken by dip net at the surface, 

 under a nightlight : Sta. 126 : 00°11' S., 08°39' E. ; 

 2000-2400 hours, April 16, 1968 ; 1,080 m., surface 

 temperature 28.8° C. ; 1 specimen, 104 mm. SL. Sta. 

 132: 00°38' N., 07°21' E.; 1900-2400 hours, April 

 17, 1968; 2,664 m., surface temperature 29.6° C; 3 

 specimens, 29.9 to 49.8 mm. SL. Sta. 138 : 01°20' 

 N., 07°55' E.; 2030-0230 hours, April 19-20, 1968; 

 2,400 m., surface temperature 28.6° C. ; 13 speci- 

 mens, 13.8 to 147 mm. SL. Sta. 152: 02°25' N., 

 06°29' E.; 2200-0200 hours, April 23-24, 1968; 

 1,520 m., surface temperature 28.9° C; 1 specimen, 

 47.9 mm. SL. Sta. 158 : 04°52' N., 05°34' E. ; 0000- 

 0215 hours, April 25, 1968 ; 240 m., surface temper- 

 ature 28.8° C. ; 16 specimens, 29.5 to 238 mm. SL. 



All study material is cataloged in the fish col- 

 lections of BCF Tropical Atlantic Biological Lab- 

 oratory, Miami, Fla. 



DEVELOPMENT AND GROWTH 



My discussion of changes during development 

 and growth concerns loss of larval characteristics, 

 pigmentations, fin rays, and relations of measure- 

 ments of various body parts. 



LOSS OF LARVAL CHARACTERISTICS 



Within the size range represented here, head 

 spines are lost, scales undergo changes, caudal 

 keels develop, and changes occur in the doi"sal, 

 anal, and ])el\ic fins. 



Head Spines 



In an earlier paper on the Atlantic sailfish 

 (Gehringer, 1957). I reported pterotic and pre- 

 opercular spines on a 101-mm. SL specimen. Voss 



178 



U.S. FISH AND WILDLIFE SERVICE 



