598 
CxEOFFREY SMITH. 
parasite was still on them, small ova were developed in the 
testes. This observation, while differing in an interesting 
manner from what occurs in Inachus, where the ova are not 
found until after recovery, yet confirms the account I have 
given for Inachus in a very convincing way. 
If we consider the facts related above in their bearing on 
the problem of the correlation of the primary and secondary 
sexual characters, it is evident that we are provided with 
some instructive evidence. In the first place we observe the 
male developing the secondary sexual characters of the 
female, and this it does, not mei’ely in a negative manner by 
returning to some intermediate, indifferent condition, as 
usually happens in the case of ordinary castration, but by 
positively acquiring characters which normally only appear 
in the adult breeding female. Now, we may hold two 
opinions with regard to these males — either that their 
resemblance to the female is a spurious one, and that the 
development of the female secondary sexual characters is 
due in them to a different cause to that which conditions 
their development in the female, or else it is a true resem- 
blance due to the same cause. That the latter alternative is 
correct is shown by the fact that these males may subse- 
quently develop typical ova, because we cannot requii’e more 
of an animal to prove its female nature than that it should 
produce ova and exhibit all the secondary characters of the 
female as well. The infected males, therefore, develop the 
female secondary sexual characters for the same reason that 
the female does. Now what is this reason in the female ? 
In the female the development of the secondary sexual 
characters is correlated with that of the ovary. Thus the 
adult form of the abdomen and the form of the abdominal 
appendages is not assumed until the ovary is ripe, while the 
atrophy of the ovary, as a result of the presence of Sacculina, 
causes the atrophy to some degree of the appendages. In 
the case of the female, therefore, we might assume that the 
ovary produces a substance or internal secretion which 
causes the development of the secondary sexual characters. 
