sea-fisheries laboratory. 299 



Explanation of the Plates. 

 Plate III. 



Fig. 1. Section of the anal fin of a plaice, made 

 transversely to the long axis of the fish and showing cysts 

 containing Trernatode parasites. Mag. 50 dia. 



Fig. 2. Gasterostomum, sp. Isolated from one of 

 the cysts represented in fig. 1. Mag. 82 dia. 



Fig. o. Gasterostomum, sp. Anterior portion of the 

 body, showing the dermal armature. Mag. -357 dia. 



Fig. 4. Gasterostomum, sp. Section of the skin 

 parallel to the long axis of the body, showing the spines. 



Fig. 5. G aster ostomum, sp. Section of the skin, 

 transverse to the long axis of the body showing the spines. 



Fig. 6. Gasterostomum, sp, Oblique surface view 

 of the spines. 



Fig. 16. Gasterostomum, sp. Corpuscles from the 

 interior of a cyst. 



Figs. 4, 5, U and 10 — Zeiss apo. 15 m. oil iniin. lens. 



Plate IY. 



Fig. 7. Gasterostomum gracilescens. Specimen from 

 the brain of the cod. Mag. 80 dia. 



Fig. 8. Gasterostomum gracilescens. Encysted larva 

 from the brain of Phycls. Mag. 80 dia. 



Fig. 9. Distomum valdeinflatum. Larva still enclosed 

 within the inner cyst. Mag. about 100 dia. 



Fig. 10. Distomum valdeinflatum. Larva isolated 

 from the cyst. Mag. 82 dia. 



Fig. 11. Gasterostomum gracilescens. Part of the 

 skin showing the dermal armature. Zeiss 1'5 mm. apo. 

 oil immers. 



