210
MARINE MOLLUSCS AS HOSTS FOR SYMBIOSES
D e s c r i p t i o n of stages in mollusc. Xporocyst (Fig. 116) long, threadlike, and branched, tangled together in host’s digestive gland, gonad and
mantle ; pale yellow in color. Cercaria (Fig. 117) typical of bucephalids,
FIas. 116-1 18. Bucephalus spp. (1 16) Portion of B. mytili sporocyst enclosing developing
cercariae ; (1 17) fully developed B. mytili cercaria (redrawn after Cole, 1935) ;
(118) fully developed Cercaria noblei (redrawn after Giles, 1962). C , Cirrus; CO,
cystogenous organ ; C P , cmus pouch ; DC, developing cercaria ; E V , excretory
vesicle ; GS, genital sinus ; H , haptor ; 08, oral sucker ; 0 V , ovary ; T, testis.
with long furcae, nearly twice as long as body, attached to anterior
surface of tail stem; tail stem comprised of median and two lateral
lobes ; body proper about 0.26-0.27 mm long, anterior holdfast (rhyn-