PARASITIC CASTRATION 



10 I 



on the Hermit-crab, Eupagurus excavatus, var. meticulosa. 1 The 

 ordinary males of /. mauritanicus have the appearance shown 

 in Fig. 72, A. The abdomen is small and bears a pair of 

 copulatory styles, while the chelipedes are long and swollen. In 

 the female (B) the abdomen is much larger and trough-shaped, 



FK;. 72. Illustrating the effect of parasitic Sacculina neglecta on Inachus mauri- 

 tanifus, nat. size. A, Normal male ; Inachus ; B, normal female ; C, male infested 

 l>y tiicculinu (final stage) ; D, abdomen of infested female ; E, infested male in an 

 early stage of its modification. 



and carries four pairs of ovigerous appendages ; the chelae are 

 small and narrow. 



Now it is found that in about 70 per cent of males infected 

 with Sacculina the body takes on to varying degrees the female 

 characters, the abdomen becoming broad as in the female, with a 

 tendency to develop the ovigerous appendages, while the chelae 

 become reduced (Fig. 72, C). This assumption of the female 

 characteristics by the male under the influence of the parasite 

 may be so perfect that the abdomen and chelae become typically 

 female in dimensions, while the abdomen develops not only the 



1 F. A. Potts, Quart. J. J//o-. Sci. 1., 1906, p. 599. 



