YOUNG JACK CREVALLES 



459 



mentation is apparent ; and paired caudal keels 

 above and below the lateral line are present. In 

 the family Carangidae, this combination of char- 

 acters is attributable only to ruber. 



Characters 



Dorsal spines. — VIII and I. All spines are well 

 formed at 12.4 mm. standard length (fig. 34). 

 The fourth spine averages the greatest length to 

 about 33 mm.; above 33 mm., t lie third spine is 

 longest. An interspinous membrane connects the 

 first and second dorsal fins (eighth and ninth 

 spines) to about 75 mm. On specimens 230 mm. 

 and 246 mm., the membrane connecting the 

 seventh and eighth spines has disappeared. 



The regression of length of the third dorsal 

 spine on standard length is shown in figure 39 and 



table 7. A line fitted to this regression for speci- 

 mens from 12.4 to 118 mm. standard length shows 

 a proportional rate of increase for the two variates 

 within this size range (0.10-mm. increase in spine 

 length per 1.0-mm. increase in standard length). 

 The coordinates of the four specimens larger than 

 118 mm. fall along the extension of the calculated 

 regression line, indicating that the spine growth 

 may continue at the same proportional rate. 



Anal spines. — II and I. All spines are well 

 formed at 12.4 mm. standard length (fig. 34). 

 The second spine is longer than the first at all 

 sizes. An interspinous membrane connects the 

 second and third spines to about 42 mm. 



Dorsal soft-rays.— 26 to 30 (table 8). Counts 

 of 2 specimens with only 24 soft-rays given by 

 Nichols and Roemhild (1946, fig. 1) could repre- 



Table 7. — Caranx ruber: Statistics describing regressions of body parts on standard length 



x = mean of independent variable z 



y = mean of dependent variable y 



A r =number of specimens 



6 = rate of increase of y 



a = y-intercept of regression line 



Syr) =standard deviation from regression (standard error of estimate) 



Independent variable x 



Standard length . 



Do _ 



Do 



Do 



Do.. 



Do 



Do 



Do 



Do 



Do.... 



Dependent variable \ 



Dorsal-fin spine length (3d). 

 Dorsal soft -ray length (1st). 



Pectoral length 



do 



Bodv depth 



do 



Head length 



Eve diameter 



....do 



Snout length 



Size range of 



specimens 



(mm.) 



12.4-118 

 12.4-118 

 12. 4-74. 5 

 74. 5-230 

 12. 4-23. 1 

 23. 1-1 OB 

 12.4-118 

 12. 4-34. 1 

 34. 1-106 

 12. I ss. 5, 



44.70 

 45.72 

 34.44 

 106. 27 

 18.61 

 52.82 

 43.91 

 22.84 

 65.50 

 38.31 



4.61 

 5.72 

 7.01 

 26. 90 

 8.67 

 19.30 

 13. 65 

 2.90 

 5.55 

 3.45 



N 



0.098 

 .121 

 .201 

 .381 

 .406 

 .294 

 .265 

 .080 

 .058 



1.708 



.174 



.094 



-13.588 



1.107 



3.776 



2.014 



1.080 



1.736 



iiyi 



0.435 

 .376 

 .336 



1.961 

 .302 

 .638 

 .523 

 .143 

 .165 

 .219 



Figure 34. — Caranx ruber juvenile, 12.4 mm. standard length (Gill 7, Reg. 71). 



