FISHERY BULLETIN: VOL. 80, NO. 2 



D 



Figure 10.— Posterior-most dorsal pterygiophore and its stay from a 668 

 mm ESL Xiphias gladius. Top, left lateral view of proximal and distal 

 radial, double ray and stay; bottom, dorsal view of stay, enlarged. For 

 abbreviations, see Figures 8 and 9. Cartilage, white; bone, stippled. 



2.0 mm 



Figure 9.— Left lateral view of the posterior- 

 most dorsal pterygiophore from Xiphias gla- 

 dius, showing the ontogeny. Starting from the 

 top and going to the bottom the specimens' 

 lengths in millimeters ESL are: 15.9, 20.4, 26.7, 

 33.6, 52.4, 225, length unknown for last on bot- 

 tom, weight 61 lb. St, stay; for other abbrevia- 

 tions, see Figure 8. Cartilage, white; ossifying, 

 stippled. 



Table 6.— Adult and juvenile position of posterior- 

 most dorsal and anal fin pterygiophores in their 

 interneural and interhaemal spaces for 116 Xiphias 

 gladius (7.1-668 mm ESL). 



Interneural space numbers 



Interhaemal space numbers 



Item 



21 



20 



21 

 21 



22 

 21 



22 

 22 



Number of specimens 29 7 79 1 



Percent of specimens 25.0 6.0 68 1 9 



Table 7). Addition of cartilaginous pterygio- 

 phores was in both anterior and posterior direc- 

 tions. The posteriormost interneural space 

 number 21 or 22 was filled first (Fig. 6; Table 7). 

 Addition of pterygiophores was then in an 

 anterior direction until the anterior interneural 



Figure 11. — Schematic presentation of common arrangement of 

 pterygiophores and fin rays in relation to neural and haemal spines and 

 vertebrae in 39 Xiphias gladius (14.7-668 mm ESL). Method of 

 presentation modified after Matsui (1967). A, skull and vertebrae 

 numbers; B, interneural and interhaemal space numbers; C, number of 

 pterygiophores with highest frequency of occurrence found in the 

 respective ("B") interneural or interhaemal space; D, number of fin rays 

 associated with pterygiophores for indicated interneural or interhaemal 

 space; E, highest frequency of occurrence in 39 Xiphias for the number of 

 pterygiophores indicated in "C"; F, range of number of pterygiophores 

 found in the respective ("B") interneural and interhaemal spaces. 



space number 2 was occupied (Fig. 6; Table 7). 

 Fin rays followed pterygiophore appearance at 

 the center of the body. Addition of rays followed 

 addition of pterygiophores, with some cartila- 

 ginous pterygiophores present anterior and 

 posterior to the developing rays (Fig. 6). 



Ossification of dorsal pterygiophores first 

 started at 6. 1 mm E N L in the same area and pro- 

 ceeded in the same direction as the cartilage 

 development. Every specimen >8.0 mm ESL had 

 some ossifying pterygiophores, and between 18.2 

 and 26.7 mm ESL all pterygiophores were ossi- 

 fying. The last pterygiophore to ossify was the 

 anteriormost in the second interneural space. 



168 



