SEA-FISHERIES LABORATORY. 271 



tracted strobila is seen inside, but without any trace of 

 segmentation. As one attempts to dissect out the latter 

 one finds that it gradually becomes fused with the sur- 

 rounding waxy tissue which is probably derived from the 

 caecum, and invariably the structure breaks. Yon 

 Linstow* describes the worm as having a pseudo-scolex 

 with two slightly developed sucking grooves and figures 

 such a head, from the intestine of Lota vulgaris, as a 

 normal structure. Probably in young codling, recently 

 infected, a stage of the cestode with such a scolex might 

 be found but doubtless with increasing age the changes 

 mentioned above occur, and the normal structure of the 

 head disappears. 



The lumen of the gut immediately behind the 

 stomach may at times be almost blocked by the strobilae 

 of these cestodes. The largest specimen found was 85 cm. 

 in total length and about 8 mm. in breadth at its 

 widest part. This worm was, however, incomplete. The 

 older proglottides contained fully developed oncosphere 

 larvae belonging to a later stage than Schauiusland's 

 Fig. 8. (Bronn, Thier-reich, Bd. 4, 1 B, PI. LVII, Fig. 8.) 

 These larvae have a fully developed mantle. They are 

 from 90 to 120 /u. in diameter. The undeveloped eggs 

 from the less ripe proglottides are much smaller, and are 

 about 30 /ul in diameter. 



Echinobothrium affine, Diesing. 



From Raia clavata, Shoals, 1906. . 



A single specimen of a small cestode, preserved from 

 the contents of the spiral valve of a large thornback ray, 

 appears to belong to this species. The worm, however, 

 differs in certain respects from both Echinobothrium typus 

 and E. affine. Fig. 9 represents the scolex, neck and the 



* Arch. f. Naturgesch., 54 Jahrg. 1888, Bd. I. 



