1913] Mivhacl: Sagitta califoniica from Sail Di<'()o Ri'ijioii llf) 



C'0RREI..\TION BETWEEN' LENGTH OF AXIMAL AND NulIBER OF SEIZING JaWS 

 Number Length of animal in mm. 



aws 12-14 14-16 16-18 18-20 20-22 22-2 



6 1 1 



(25) (17) 



7 2 3 3 3 9 5 

 (50) (59) (59) (25) (25) (6) 



8 1 .... 2 9 20 38 

 (25) (33) (75) (56) (44) 



9 .... 2 1 .... 7 43 



(33) (17) (19) (50) (45) 



10 



(3) 



Total 4 6 6 12 36 



r= 0.4566 ±0.0372 



SUMMAEY 



We have discovered in this discussion of variation and correla- 

 tion many facts of specific importance as follows : 



1. In animals between 12 and 26 mm. in length, variation in 

 the ratio Ijetween length of animal and length of tail, interval 

 from tail to ventral ganglion, length and width of anterior fin. 

 interval from anterior fin to ventral ganglion, and length and 

 width of posterior fin — is approximately constant, irrespective 

 of the length of animal. Of all proportional measurements these 

 are, therefore, the safest for the identification of S. califoniica. 

 and this is especially true of the proportional length of tail. 



2. In animals between 12 and 26 mm. the width of body, 

 interval between anterior and posterior fins, interval from pos- 

 terior fin to seminal vesicle, and length of ovary increase more 

 rapidly than the animal increases in size, while the ventral 

 ganglion increases less rapidly than the animal does. Therefore, 

 the ratio between these various measurements and length of 

 animal is of certain specific value only for animals of definite 

 leneth.s. 



