lOOS 

 800 



'^ 200 

 9 100 



50 



TOTAL BODY LENGTH (cmj 



FIGURE 4.— Testes weights in relation to body length. The stip- 

 pled area indicates the region of overlap for mature and imma- 

 ture testes weights. 



1 ' r 



-T-: 





M, 



140 160 



• * 



• * 



80DY LENGTH 



Figures. — Ovarian corpora related to body length mDelphinus 

 delphis. The range of body lengths in which sexually mature and 

 immature animals cannot be distinguished is indicated by the 

 strippled area 



range of FI scores (Figure 7) and there is no sig- 

 nificant relationship between the number of ovar- 

 ian scars and the FI (P >0.10, Kendall's rank cor- 

 relation). 



Robustness is here defined as the body length in 

 centimeters divided by body weight in kilograms. 

 Regardless of body length, only the most robust 

 individuals are sexually mature. Sexual maturity 

 occurs when the male's length/weight ratio de- 



298 



FLIPPER INDEX 



Figure 6. — Development of testes related to epiphyseal de- 

 velopment of the pectoral appendages in Delphinus delphts as 

 indicated by the Flipper Index, The best interpretation of the 

 present data is that two linear phases are separated by a stage of 

 rapid change. 



T ' r 



i ' — I — ' — r 





Figure 7. — Ovarian corpora related to pectoral epiphyseal de- 

 velopment (Flipper Index) \n Delph in usdelphis. The shaded area 

 indicates the range in Flipper Index over which sexually mature 

 and immature animals overlap. 



clines to about 2.6 (Figure 8). Mature females had 

 length/weight ratios lower than about 3.0 (Figure 

 9). Of the 24 females with ovarian scars in this 

 study, 16 were pregnant. Assuming the weight of 

 the amniotic sack is nearly equal to that of the 

 fetus, twice the weight of the fetus was subtracted 

 from the gross weight of the mother, leaving the 

 weight of the nonpregnant female for calculations 

 of robustness. The robustness of the pregnant 

 females is not separable from the sexually mature 

 nonpregnant females. 



