3i8 



DISCOVERY REPORTS 



It was found impossible to do more than draw up a very rough classification of the 

 females examined. No very definite distinction could be made between unripe females, 

 in which the gonads were transparent, and maturing females, in which the ripening eggs 

 could be detected as a dark border to the gonad. This dark border appears first as a line 

 along the margin of the gonad only less transparent than the gonad itself. Similarly it 

 was very often difficult to distinguish between maturing females in which the eggs were 

 almost ready to be shed and ripe females in which the eggs were evidently fully ready to be 

 shed. Four classes, then, of adult females have been very roughly distinguished : namely, 

 unripe females, maturing females, ripe females and spent females. It is possible, how- 

 ever, that among the "unripe females" are some in which the incipient dark border of 

 ripening eggs could be seen, while the class " maturing females " is a very indefinite one 

 and includes all those in which the eggs form a dark border to the gonad. It may, 

 therefore, include many ripe females. Similarly, the class "ripe females" may include 

 many very nearly mature specimens in which the large bead-like eggs could be seen in 

 the oviducts but were not really ready to shed. 



The numbers of each of these four classes of adult females found in each sample 

 examined have been tabulated below together with the percentage of each class in the 

 total sample. The number of females examined was 50 in most instances, but it will be 

 seen that at several stations, at which the major part of the catch consisted of juveniles, 

 considerably less than 50 females were examined. 



Degree of maturity of adult females of Rhincalanus gigas, 

 October 1932 to March 1933 



