Table 4.— Summary of dorsal fin ray development for 

 208 Xiphias gladius (3.7 mm ENL-225, 668 mm ESL). 



Figure 6.— Schematic representation of 

 dorsal and anal fin and pterygiophore 

 development in Xiphias gladius in relation 

 to the vertebral column and head. Pterygio- 

 phores are represented white when cartilagi- 

 nous and black when ossifying. Scales 

 represent interneural and interhaemal 

 space numbers and points on scales align 

 with tips of neural and haemal spines. 



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was in an anterior and posterior direction. The 

 posterior part of the dorsal fin was complete at a 

 smaller size before the anterior part. Adult 

 dorsal fin counts of 44-49 rays (14.6-668 mm 

 ESL, N = 38, X = 46.4, SD = 1.23) were first ob- 

 served at 8.1 mm ESL, and all specimens longer 

 than 13.8 mm ESL had the adult count (Fig. 6; 

 Table 4). Our counts are in agreement with 

 Arata (1954). Some of Arata's specimens, how- 

 ever, did not have adult counts. The sequence of 

 dorsal fin ray development is similar in Xiphias 

 to that of Curyphaena reported by Potthoff 

 (1980). 



DORSAL FIN PTERYGIOPHORES 



In juvenile and adult specimens of Xiphias 

 14.1-668 mm ESL, the pterygiophores consisted 

 of a jointed proximal and distal radial support- 

 ing a fin ray. The distal radial was located 

 between the bifurcate base of the fin ray. Each 

 proximal and distal radial and fin ray were 

 forming a series, hence a serial association. Each 



fin ray also closely approximated the following 

 posterior pterygiophore in a secondary associa- 

 tion. Distal radials were present for all fin rays in 

 14 out of 37 juvenile specimens. Of the remaining 

 23 specimens 19 had one anteriormost ray and 4 

 had two anteriormost rays without distal radials 

 (Table 5). Exceptions to the serial and secondary 

 fin ray associations were found at the beginning 

 and end of the fins. The anteriormost pterygio- 

 phore supported from one to three rays, most 

 often two (Fig. 7). This pterygiophore consisted 

 of one piece of cartilage, or of a Y-shaped piece, 

 or of two fused pieces (Figs. 7, 8). In 1 of 38 speci- 



Table 5.— Percent and number of anterior dorsal and anal fin 

 rays without distal radials for 37 Xiphiasgladius( 14.7-668 mm 

 ESL). Percent and number under are specimens in which all 

 fin ravs had distal radials. 



166 



