4l6 fVilliam Morton Wheeler 



crab (Eriphia) examined by Smith there was infection both bv 

 Saccuhna and by a parasitic Isopod crustacean. Here the nature 

 of the parasite governs the result, and crabs with Saccuhna alone 

 never showed the least trace of modification, while changes closely 

 similar to those described above occurred in those which har- 

 boured the Isopod." 



Geoffrey Smith ('05 b) has also described parasitic castration 

 in Inachus dorsettensis by a sporozoon (Aggregata inachi) which 

 lives in the intestine of the crab and induce^ modifications not 

 unlike those induced by Sacculina. Smith says that of fifty males 

 of I. dorsettensis examined, "seven specimens were clearly dis- 

 tinguished by having the flat chelae characteristic of the females, 

 while the abdomen was much broader than is the case in normal 

 males of a corresponding size, thus converging on the female con- 

 dition. In one specimen there was present on the under side of the 

 abdomen a pair of swimmerets which are characteristic of the 

 female, these appendages being altogether absent in the normal 

 males." Dissection of these crabs showed the intestine "to be 

 covered with cysts of Aggregata inachi, the body cavity was also 

 full of liberated sporozoites, the haemolymph having a milky ap- 

 pearance due to the crowded presence of these bodies. The testes 

 were in all cases disintegrated, only the vesiculae seminales remain- 

 ing. Two modified males were also found to contain the cysts of 

 Aggregata inachi, but in none of these males were there larger 

 quantities of sporozoites in the haemolymph, so that it appears 

 that the hermaphrodite external characters are assumed by the in- 

 fected male at the moult which follows the liberation of a large 

 quantity of sporozoites." Smith made no observations on the 

 infected female Inachus, as this sex is much rarer than the male. 



The foregoing examples of parasitic castration in Crustacea have 

 been reviewed at some length, because they show the phenomenon 

 in its most striking manifestation. Giard as early as 1888 (/') 

 published a long list of other animals and plants known to be cas- 

 trated by what he calls "gonotomic" parasites. The most inter- 

 esting examples, apart from Andrena and the Crustacea just con- 

 sidered, are the castration of the nemertean Lineus obscurus bv the 

 orthonectidIntoshialinea,of the planarian Leptoplana tremellaris 



