266 Larval Flukes from China 
7. Further study along these lines will make it possible to demonstrate 
natural groups where only artificial groups now exist. 
EXPLANATION OF PLATES XXI—XXII. 
Note. The line at the side of each figure has a value of 0-01 mm. 
PLATE XXI. 
Fig. 1. Cercaria plana, ventral view, x 145. 
Fig. 2. Cercaria nervosa, ventral view, x 190. 
Fig. 3. Cercaria syringicauda, dorsal view, showing body, syringe bulb and terminal excretory 
tube, x 236. 
Fig. 4. Cercaria serpens, ventral view, x 440. 
Figs. 5, 6. Cercaria cristacantha. Fig. 5, ventral view of the cercaria. x 90. Fig. 6, lateral view of 
the redia. x 34. 
Figs. 7-11. Cercaria leptoderma. Figs. 7-10, developing stages of the larva showing differentiation 
of the excretory system. Fig. 11, detail of the mature cercaria. x 200. 
PLATE XXII. 
Fig. 12. Cercaria stylobuccalis, dorsal view, x 170. 
Fig. 13. Cercaria styloidea, dorsal view, x 256. 
Fig. 14. Cercaria diophthalmica, dorsal view, x 338. 
Fig. 15. Cercaria acrodonta, dorsal view, x 398. 
Fig. 16. Cercaria circumstricta, dorsal view, x 486. 
Fig. 17. Cercaria photifera, dorsal view, x 245. 
Fig. 18. Cercaria chromophila, ventral view, x 358. 
Fig. 19. Cercaria, abbrevicauda, ventral view, x 350. 
LEGEND FOR FIGURES. 
aeg, acidophilic cephalic gland; b, excretory bladder; beg, basophilic cephalic gland; cb, caudal 
bulbus of excretory apparatus; ce, caecal epithelium; eg, cystogenous glands; cgd, cephalic gland 
ducts; cp, caudal excretory tube; eg, excretory granules; ep, excretory pore; ga, ga x , ga 2 , genital 
anlagen; IC, Island of Cort; ict, inner collecting tubule; le, lateral eye; Ip, lateral excretory tube; 
Isp, lateral suctorial pocket; met, median collecting tubule; me, median eye; oa, outer acetabular 
disc; os, oral sucker; ost, origin, secondary collecting tubule; peg, pharyngeal gland; ph, pharynx; 
pgd, pharyngeal gland duct ; pp, pharyngeal pocket ; s, stylet. 
REFERENCES 
Cort, W. W. (1915). Some North American Larval Trematodes. III. Biol. Monogr. i. 447- 
532, 8 Pis. 
- (1919). A New Cercarieum from North America. Journ. Parasitol. v. 86-91, 1 PI. 
Cort, W. W. and Nichols, E. (1920). A New Cystophorous Cercaria from California. Journ. 
Parasitol. vn. 8-15, 2 Text-figs. 
Faust, E. C. (1919). The Excretory System in Digenea. II. Observations on the Excretory 
System in Distome Cercariae. Biol. Bull, xxxvi. 322-339, 10 Text-figs. 
- (1919 a). The Excretory System in Digenea. III. Notes on the Excretory System 
in a Monostome Larva, Cercaria spatula nov. spec. Biol. Bull, xxxvi. 340-344, 3 Text- 
figs. 
- (1919 b). A New Trematode, Acanthatrium nycteridis nov. gen., nov. spec., from the 
Little Brown Bat. Trans. Amor. Micr. Soc. xxxvm. 209-215, 2 Pis. 
- (1921). The Excretory System in Digenea (Trematoda). IV. A Study of the Structure 
and Development of the Excretory System in a Cystocercous Larva. Cercaria pekinensis 
nov. spec. Parasitology, xiii. 205-212. 
