0. THE PHYLA PORIFERA, CNIDARIA AND PLATYHELMINTHES
251
FIGS. 169-167. Larval allocreads and trematodes of undetermined taxonomic positions.
(169) Metacercaria of Lepocreadium album enveloped by gelatinous coat ; (160)
young adult of L. album recovered from intestine of definitive fish host; (181)
Metacercaria acherusiae escaping from cyst (redrawn after Palombi, 1934a) ;
(162) Metacercaria mytili within cyst wall ; (163) sporocyst of Cercaria buccind;
(164) fully developed C. buccini (redrawn after Lebour, 191 1) ; sporocyst of Cercaria
tenuans; fully developed C. tenuans (redrawn after Cole, 1936) ; unidentified
“ aporocyst ” of Nicoll (redrawn after Nicoll, 1906b). C, Cyst; C I R , cirrus; DO,
developing ovary ; DS, ‘‘ daughter sporocyst ” ; D T , developing testis ; ES, eyespot; E V , excretory vesicle; BP, genital pore; I N T , intestinsl caecum; MC,
metacercarial cyst ; PO, penetration (cephalic) gland; P H , pharynx; ST, stylet.