IZ9 130 131 132 133 134 135 136 137 13 14 15 16 17 18 IS 

 VERTEBRAL COUNT LEFT PECTORAL FIN RAYS 



X ± 95 % C I = 2 72 8 ± 5 3 



X 1 95% C I = 165 +0 2 



?77pL ^__ _, 



230 240 250 260 270 2aO 290 300 310 14 15 16 17 18 19 20 

 DORSAL FIN RAYS CAUDAL FIN RAYS 



x± 95% C I = 244.3+ 5 I 



X ± 95% CI. = 15 9± 4 



< 



< 



a: 

 o 

 o 



300- 



280 



260- 



240- 



220 



200 



— r~ 

 220 



T 



T" 



"T" 



240 

 ANAL FIN RAYS 



—I — 

 260 



86Xj + 62 6 

 r = 77 

 r^x 100 = 59% 



280 



Figure 3.-Regression relationship between dorsal and anal fin 

 rays of Synaphobranchus affinis elvers, where y = dorsal fin 

 rays, x = anal fin rays, r = correlation coefficient, and r^ x 100% 

 = coefficient of determination. 



ANAL FIN RAYS 



LEFT BRANCHIOSTEGALS 



Figure 2.-Means, 95% confidence intervals (C.I.), and frequency 

 distributions of various meristic characters of Synaphobranchus 

 affinis elvers. 



anal fin rays showed a great degree of variability 

 which is also characteristic of the American eel, 

 Anguilla rostrata (Wenner 1972), and the snake 

 eel, Pisodonophis cruentifer (Wenner unpubl. ob- 

 servations). Dorsal fin rays had extremes of 243 

 and 309 whereas anal fin rays had extremes of 219 

 and 271. Plots of dorsal against anal fin rays sug- 

 gested a correlation and therefore the linear 

 regression equation, correlation coefficient, and 

 coefficient of determination were calculated 

 (Figure 3). Fifty-nine percent of the variation in 

 the number of dorsal fin rays was associated with 

 the number of anal fin rays. 



Mean length of the S. affinis elvers was 89 mm 

 with extremes of 72 and 105 mm. Length- 

 frequency distribution is found in Figure 4. 

 Means, 95% confidence intervals, and extremes for 

 morphometrical measurements are given in Table 

 1. All values fell within the ranges of those of S. 

 affinis presented by Robins (1971). 



Osteological deformities associated with the 

 vertebral column were found in 72.5% of the 40 

 elvers and in 60% of the larger S. affinis examined. 

 In both instances, most deformities were in the 

 caudal part of the vertebral column, generally in 

 the last 30 vertebrae. Illustrations of some 

 representative deformities are shown in Figure 5 



X ± 95% CI = 



84 9 + I 4mm 



75 80 85 90 95 100 105 

 SIZE INTERVALS (mm) 



Figure 4.-Frequency distribution, mean, and 95% confidence 

 interval (C.I.) of total length of Synaphobranchus affinis elvers. 



Table 1.— Summary of morphometric characters of elvers of 

 Synaphobranchus affinis. C. I. refers to confidence interval. 



and a summary of the major types is in Table 2. X^ 

 analysis showed that there was no significant 

 difference between elvers and larger immature 

 fish (X^ = 1.72, df = 39), suggesting that these 

 deformities do not result in differential mortality 

 in fishes possessing them. 

 It is conjectural whether these specimens 



689 



