FISHERY BULLETIN: VOL. 80, NO. 2 



anterior orbit of the eye to the tip of the notochord 

 (ENL) and those after notochord flexion were 

 measured from the anterior orbit of the eye to the 

 posteriormost edge of the hypural bones (ESL). 

 The measurements were taken to the nearest 0.1 

 mm with a calibrated ocular micrometer for 

 specimens <20 mm ESL, and for those >20 mm 

 ESL, dial calipers were used. The reason for 

 using ENL and ESL rather than standard 

 length (SL) was that in most specimens the 

 sword (bill) was damaged and standard length 

 measurement would have been inaccurate. 



A series of 220 Xiphias gladius from 3.7 mm 

 ENL to 668 mm ESL captured with plankton 

 nets, or by night light and dip netting, or taken 

 from dolphin fish, Coryphaena hippurus, 

 stomachs were cleared and stained for cartilage 

 and bone by a combined method after Taylor 

 (1967) and Dingerkus and Uhler (1977). Mea- 

 surements of the specimens were taken after 

 clearing and staining, because almost all 

 Xiphias were twisted before clearing but were 

 easily straightened after the clearing. 



Although we had many smaller sized Xiphias 

 larvae, we could have used more juveniles for our 

 study (Fig. 1). Most of our specimens were col- 

 lected in the Gulf of Mexico but a few were 



caught in the Caribbean Sea and Atlantic Ocean 

 (Fig. 2). 



All specimens were examined in 100% glycerin 

 and under 100X to 150X magnification with a 

 high-quality binocular dissecting microscope. 

 Cartilage was viewed with the help of alcian blue 

 stain, but cartilaginous structures that some- 

 times stained weakly or not at all were viewed by 

 manipulating light intensity and the angle of the 

 substage mirror. Onset of ossification was deter- 

 mined by light (pink) alizarin uptake, usually 

 around the margin of a structure. Illustrations 

 were drawn with the help of a camera lucida. 



The osteological terms used in this study follow 

 those used by Gosline (1961a, b), Nybelin (1963), 

 Gibbs and Collette (1967), Monod (1968), and 

 Potthoff (1975, 1980). 



Counts of pterygiophores and fin rays include 

 very small vestigial structures. 



PECTORAL FIN 



The pectoral fin rays in Xiphias were the first 

 of all fin rays to begin development. The first 

 rays were present at 4.8-5.6 mm ENL (Tables 1, 

 2). Development of the rays started on the dorsal 

 border of the larval fin blade and proceeded in a 



Figure 1.— Length-frequency distribution of cleared and 

 stained Xiphias gladim used for this study. 



131 188 225 668 



4 5 5.5 6.5 7.5 8.5 9.5 10 5 115 12 5 13 5 14 5 15 5 16 5 17 5 18 5 19 5 20 5 25 5 35 5 45 5 65 5 



LENGTH.mmENLor ESL 



162 



