
JOHNSTON AND BECKWITH—LARVAL TREMATODES 569 
(fig. 7 and 9), the bipartite nature of the body is obvious, the posterior part 
containing the genital primordia being much smaller than the anterior contain- 
ing the organs of adhesion. These comprise two lateral suctorial cups (fig. 7), 

Fig. 7-11, Cercaria lessoni. 7. metacercaria freed from cyst, ventral view; 8. cyst; 
f. metacerearia, lateral yiew; 10. metacerearia within cyst, ventral view (inner wall only of eyst 
shown); 11. a number of Apatemon cereariae arranged in series according to the disposition of 
the gland-eells—a, Cerearia of Apatemon gracilis (after Szidat) ; b, C, ripont (after Brackett) ; 
ec, C. pseudoburti: (after Rankin); 4, C. burti (after Miller); e, C. helvetica XXXI (after 
Dubois) ; £, C. pygocytophora (after Brown) ; g, C. leasoni. 
and two large suctorial lips enclosed in a ventral pocket. The anterior and 
ventral suckers are well-developed. .A pharynx was not seen, but in figures 
of the closely similar Tetracotyle of Apatemon gracilis, described by Szidat 
(1931, 143-4), a very faint pharynx is indicated. 
