194 CARL L. HUBBS. 



of the young may also be correlated with selective mating, espe- 

 cially in view of the natal maturity of the males. 







PERIOD OF BREEDING OF FEMALES OF DIFFERENT SIZE AND AGE. 



The following table gives the average length of the young 



found in each of fifty one- and three-year-old 1 females of Ainphi- 



TABLE I. 



SIZE OF YOUNG OF AMPHIGONOPTERUS AURORA CARRIED BY FEMALES OF DIF- 

 FERENT LENGTH AND AGE. 



Average Length of Young Lengths of Females Carry- Age of Females (End 

 (in mm. to Base of ing Young of Foregoing of Given Year 



Caudal) Length. since Birth). 



12... .... 77 I.(i) 



13 96 I. (i) 



M 85 I. (i) 



IS 84 I. (i). 



16... ... 76,77,82,85 I. (4) 



17 77,86,90,95 I. (4) 



18 78,81,84,85,88,94 I- (6) 



i9 . 8^87,92 I. (3) 



20 88, 88 I. (2) 



21. .. 92, 94,95,98,98,99 I- (6) 



85,87,91 I. (3) 



23 



24 102; 122 I. (i) ; III. (i) 



25 95, 103 I. (2) 



26 103 I. (i) 



27 1 02 I.(i) 



28 95,96; 118 I.(2); III. (r) 



29 112 III. (i) 



30 



31 126 III. (i) 



32 121, 123, 128 III. (3) 



33 122, 123, 128 III. (3) 



34 129 HI. d) 



gonoptcms, all of which were obtained near Piedras Blancas. 

 California, during the first week of June, 1916. Both adults and 

 embryos were measured when freshly caught, prior to their 

 preservation. The smallest young are not nearly developed to the 

 stage at which they are born : it is improbable that the smaller 

 females give little to young notably smaller than those of the 

 larger females. 



1 The method of age-determination by scale examination will be discussed 

 later. 



