PARASITISM AND SYMBIOSIS
PARASITISM AND SYMBIOSIS cypridian : by this kind of trocar (Fig. 35 V) the cypridian cellular mass is, so to speak, injected into the body cavity of the crab. Delage named this larval stage the kentrogon. The cypris larva is thus changed into a small cellular mass, naked and undifferentiated, and now within the body of the crab. There has taken place, then, a very great regression, beginning in the free-living stages and particularly from the ancestral cypris in which there were already the rudiments of all the essential organs of the adult cirripede. Sacculina will remain as an internal parasite of the crab for a very long time, according to Delage about twenty months, during which the crab completes its growth. Its history during this period was elucidated by G. Smith,* who confirmed 274 and, in 1906, definitely placed beyond dispute the facts set out by Delage, which had been contested, particularly by Giard, on account of their peculiar nature. The internal, undifferentiated ...