35 
The life history of Acanthopsolus lageniformis may be thus 
summed up : — 
First Host. Intermediate Host. Final Host. 
Buccinum undatum. Omitted. Anarrhichaa lupus. 
Inhabiting liver. Inhabiting intestine. 
(Rediae containing 
cercarite). 
Plate I. 
Fig. 1 . — Acanthopsolus lageniformis from intestine of Catfish— ventral view 
(natural size 0'80 mm.) 
o.s. 
Oral sucker. 
P.PH. ... 
Prepharynx. 
E. 
Eye. 
PII. 
Pharynx. 
G.P. 
Genital pore. 
V. 
Vitellaria. 
V.SEM. ... 
Vesicula seminalis. 
P.P. 
Pars prostatica. 
V.S. 
Ventral sucker. 
O. 
Ovary. 
EG. 
Egg. 
V.D. 
Vas deferens. 
V.G. 
Vagina. 
R.S. 
Receptaculum semin is. 
T. 
Testis. 
E.V. 
Excretory vesicle. 
Fig. 2. — Side view of same. 
„ 3. — Young redia (natural size 0’30 mm.) from liver of Buccinum undatum. 
„ 4. — Small redia containing cercaria (natural size 050 mm.) 
„ 5. — Large redia containing cercaria (natural size 3'20 mm.) 
„ G. — Anterior end of redia showing pharynx and intestine, and one contained 
cercaria (greatly enlarged). 
„ 7. — Cercaria with tail (natural size of body 0'50 mm.) 
„ 8. — Cercaria without tail (natural size 0‘50 mm.) ; glands near oral sucker. 
LIST OF REFERENCES. 
1. — Nicoll — “A Contribution towards a Knowledge of the Entozoa of British 
Marine Fishes,” Part II. Ann. and Mag. Nat. Hist. (8) IV. (1909), p. 15. 
2. — Odhner — “Die Trematoden des Arktischen Gebietes,” p. 328 (1904). 
3. — Lebour M. V. — “Notes on Northumbrian Trematodes,” Northumberland 
Sea Fisheries Report for 1905, p. G (190G). 
