58 MARIE V. LEBOUR. 
From these observations it seems that there is no encysted stage in this 
species, the period passed in the medusa serving the same purpose. 
Probably this period is very short, the mackerel swallowing the host soon 
after the entry of the parasite, and for this reason an encysted stage is 
not necessary. 
Nothing is at present known of the early stages in the life history of 
Pharyngora, although it is to be inferred that a mollusk is the first host. 
Fie. 1.—Pharyngora bacillaris. » 120. ED, excretory duct; EP, excretory pore; EV, 
excretory vesicle ; IC, intestinal cecum; CES, cesophagus; OS, oral sucker ; 
PH, pharynx; PPH, prepharynx; PCS, pseudo-cesophagus ; VS, ventral 
sucker. 
The larval worm is very like the adult, but without reproductive 
organs (see Hig. 1), and bears a close resemblance to Nicoll’s figure (Plate 
XXIX, Fig. 5). The body is covered with minute spines; the curiously 
shaped oval sucker is conspicuous ; ventral sucker, prepharynx, pharynx, 
cesophagus, pseudo-ccsophagus, and intestinal ceca all agree with the 
