110 Viiiversifij of Calif ornia Publications in Zoology [Vol. 11 



Length of animal Calculated Actual 



in mm. average average 



12-14 a..? per cent 3.9 per cent 



14-16 7.5 per cent 8.7 per cent 



16-18 7. -5 per cent 6.2 per cent 



18-20 7.5 per cent 7.0 per cent 



20-22 10.1 per cent 10.8 per cent 



22-24 16.7 per cent 17.0 per cent 



24-26 21.0 per cent 21.7 per cent 



Comparison of the calculated and actual averages reveals 

 little difference, especially in the larger and more numerous 

 animals. It is quite safe, therefore, to conclude that, if based 

 on a fairly large number of measurements, the average length 

 of ovary in S. californica will vary with the length of animals 

 measured, as follows : 



0-5 per cent in animals between and 14 mm. 



5-10 per cent in animals between 14 and 20 mm. 



8-15 per cent in animals between 20 and 22 mm. 

 15-19 per cent in animals between 22 and 24 mm. 

 19-25 per cent in animals between 24 and 26 mm. 



Length of Tail. — Preparing a correlation table, as given 

 below, between length of tail as measured in per cent and length 

 of animal, we see that there is very little if any definite relation 

 between the larger animals and proportional length of tail. 



TABLE 7 



Correlation between Length of Anim.\l .\xd Proportional Length 



OF T.\1L 



