156 



HEREDITY AND SEX 



sacculina, 70% of both males and females showed 

 alterations in their secondary sexual characters. 



As a control, 5000 individuals not infected were ex- 

 amined, only one was unusual, and this one was a her- 

 maphrodite (or else a crab recovered from its parasite). 



FIG. 79. - A male of Inachus mauritanicus (upper left hand). Female of 

 Inachus scorpi (lower left hand) . Male of Inachus mauritanicus carrying on 

 its abdomen two specimens of Danalia curvata and a small Sacculina neglecta 

 (upper right hand). Male of Inachus mauritanicus with a Sacculina neglecta 

 on it (lower right hand). The abdomen and chelae of the host are inter- 

 mediate in character between those of an ordinary male and female. (After 

 Geoffrey Smith.) 



As the figures (Fig. 80) show, the adult male has 

 large claws ; the female, small ones. He has a narrow 

 abdomen; she has a broad one. In the male there 

 is a pair of stylets on the first abdominal ring (and 

 a pair of greatly reduced appendages behind them). 

 The adult female has four biramous abdominal append- 

 ages with hairs to carry the eggs. 



