1911] Michael: Chaetognatha of tlie San Diego Region. 57 



From these data we may arrive at the following tentative con- 

 clusions : 



1. The ovary commences development first but, as a rule, 



it reaches maturity at the same time as the seminal 

 vesicle. 



2. The mature ovary (pi. 5, fig. 39) varies in length from 



5 to 10 per cent of the total length of the animal, or 

 from 0.7 to 1.4 mm. 



3. In width the mature ovary varies from slightly under 



one-sixth to slightly over one-third its length. 



4. In extent the mature ovary never reaches the anterior 



limit of the posterior fin. 



So far as I am acquainted with the literature, Ritter-Zahony 

 (1908) has been the only investigator who has attempted to make 

 a systematic tabulation of the length of ovary. From his records 

 for 8. enffata I have extracted the following data : 



Length of specimen Length of ovary 



in mm. in mm. 



9 0.25 



10 0.25 



11 0.25-1.0 



12 0.60 



13 1.00-1.8 



14 0.80 



15 0.50-1.2 



16 0.50-1.1 



17 0.70-2.2 



18 1.00-1.8 



19 1.00-1.5 



20 0.90-1.6 



21-23.3 1.50-2.0 



A comparison of these data with the above table shows an 

 agreement much closer than anyone would have expected. Taken 

 as a whole, the ovary in his specimens attains a greater length 

 (2.2 mm.) that those from San Diego (1.4 mm.). 



