PLATE XXL 



Fig. 



1. Transverse section of a specimen of Linens gesserensis in which the ova are well developed. 



The shrunken condition of the walls of the digestive cavity (/), with the numerous 

 gregariniform parasites, is in strong contrast with the state of the animal after spawn- 

 ing. The specimen had been in spirit a considerable time before dissection. X 55 

 diam. 



2. Transverse section of Cephalothrix linearis. The proboscis is coiled in its sheath. 



X 90 diam. 



3. Transverse section of one of the Lineidce from St. Magnus Bay, Shetland, in which the 



sheath for the proboscis is surrounded by the internal longitudinal muscular coat. 

 X 28 diam. 



4. Transverse section of Borlasia Elizabeths after contraction in spirit. The enormous 



muscular mass forming the body-wall is well shown in this preparation. X 24 diam. 



5. Transverse section of the proboscis of Lineus marinus. X 55 diam. 



6. Transverse section of a lateral nerve-trunk (n) in Lineus gesserensis. n\ fibro-granular 



matrix, in which the nerve lies in its own proper sheath ; e, external longitudinal muscular 

 layer of the body-wall ; e, circular muscular layer. X 700 diam. 



7. Cellular elements of the wall of the digestive chamber of the same species. X 700 diam. 



8. Cells from the digestive cavity of a young Cephalothricc linearis. X 700 diam. 



9. Head and proboscis of a remarkable variety of Carinella brought from Shetland by 



Mr. Gwyn Jeffreys. b, frilled arrangement, apparently homologous with the 

 superior lip of the cephalic fissure ; w, prolapse of textures from mouth. Magnified 

 under a lens. 



10. Spermatozoa of Lineus gesserensis. X 700 diam. 



11. Spermatozoa of Lineus sanguineus. X 800 diam. 



12. Spermatozoa of Lineus marinus, from a fragmentary specimen. X 900 diam. 



13. Spermatozoa of Cephalothrios linearis. X 900 diam. 



