RUDDER FISHES IN THE WESTERN NORTH ATLANTIC 



455 



Table 3. — Number of dorsal and anal soft-rai/s on IIS 

 speci7nens of Kyphosiis sfctatrix 



Number of dorsal soft-rays 



n 12 13 



Note.— Open figures denote numbers; figures in parentheses denote per- 

 centages of specimens having respective combinations of numbers of soft-rays. 



Tlie last spine is pointed but still segmented, 

 indicating near completion of a transition from a 

 segmented ray to an unscgmented spine. Similar 

 development has been noted in anal spines of 

 mullet (Anderson, 1957) and striped bass (Man- 

 sueti, 1958). The transition completes the com- 

 plement of the dorsal spines. 



The spines are not inserted in a single mid- 

 dorsal row, but rather alternately to the left and 

 right of the mid-dorsal line. The interspinous 

 membrane is nearly mid-dorsal in position, thus 

 attaching to alternate sides of consecutive spines. 



At 10.4 mm., all soft-rays are unbranched, ex- 

 cept for the last which is divided to its base, all 

 are segmented and the tips are all flattened. The 

 next to last ray is branched by 13.1 mm., and by 

 15.4 mm., all but the first three soft-rays are 

 branched (including both elements of the last). 

 By 21.5 mm., all but the first soft-ray are branched, 

 and by 26.4 mm., all soft-rays are branched. 



Anal fin.— Ill (59 specimens) or IV (1 speci- 

 men) — 9 (1 specimen), 11 (109 specimens), or 12 

 (5 specimens) (table 3). The full complement of 

 rays is present by 10.4 mm., the soft-raj's are 

 segmented with tips flattened and the last ray is 

 branched to its base (see fig. 1, 10.5 mm.). In 

 an 8.7-mm. K. incisor the third ray is segmented 

 and pointed, indicating a transition from seg- 

 mented ray to unsegmented spine. Although I 

 have no K. sedatrix that small, I expect the transi- 

 tion to occur in this species also. No ailditioiial 

 soft-rays are branched by 13.2 mm. By 15.0 mm., 

 the next to last and the anterior element of the 

 last ray are branched (fig. 2), by 15.4 mm., 10 

 soft-rays are branched, and by 21.5 mm., all are 

 branched. The first two spines articulate with 

 the same bone in the only specimen liaviug four 

 anal spines. 



Pectoral fin.— 17 (8 specimens), 18 (77 speci- 

 mens), or 19 (25 specimens) soft-rays (table 4). 

 The full complement of rays is present by 10.4 

 mm. (see fig. 1, 10.5 mm.). In a 10.5-mm. 

 cleared and stained specimen all but tlie first and 

 last rays have flattened tips, all l)iit the first and 

 the last three rays are segmented, and all are un- 

 branched. By 15.4 mm., initial l)ranching has 

 started in eight of the middle rays, and by 26.9 

 mm., all are segmented, and all but tlio first two and 

 the last two are branched. By 52 mm., the fiist two 

 rays and the last ray are still unbranched, thougli 

 secondary brandling lias commenced in the 10 

 iniddle rays. The last ray is branched by 71.5 

 mm., but the first two rays remain unbranched 

 to at least 260.0 mm., the largest specimen 

 examined. 



Feline fin. — I, 5 (53 specimens). Full com- 

 plement of one spine and five soft-rays is present 

 by 10.4 mm., with all five soft-rays segmented and 

 the iniddle three branched (see fig. 1, 10.5 mm.). 

 By 13.1 mm., the remaining soft-rays have also 

 branched. 



Caitdalfin. — 9 + 8 principal rays (50 specimens) 

 and 9 + 9 secondary rays in a fully formed caudal 

 fin. By 10.5 mm., all the principal rays are 

 formed, with tips flattened (fig. 1), 8 + 8 second- 

 ary rays are present, and the two secondary 

 rays adjacent to the principal rays in both dorsal 

 and ventral lobes are segmented. By 13.1 mm., 

 the principal rays have begun to branch, and by 

 15.0 mm. (fig. 2), branching is complete (the 

 dorsalmost principal ray and ventralmost prin- 

 cipal ray do not branch). The complement of 

 secondary rays is complete (9 + 9) in a 15.4-mm. 



Table 4. — Number of pectoral fin-rays on 110 specimens of 

 Kyphosus sectatrix and 71 specimens of Kyphosiis 

 incisor 



[Arranged by species and area of capture] 



619392 O— 62- 



