XXn DESCEIPTTON OF PLATES. 



FIG. 



2. Male Ech inorhynclius anthvris (x 8 diam.). 



3. A loose ovarian vesicle, containing germs in various stages of development. 



4. A series of the germs isolated. 



5. Anotlier loose ovarian vesicle with, its germ-contents rather more advanced. 



6. Antero-posterior view of a fully-developed egg, enclosed in its primitive 



envelope. 



7. Another example viewed laterally. 



8. Ovum separated from its primitive envelope, showing the shell (chorion), and 



superfluous yelk mass still adherent. (The last six figs, x 350 diam.) 



9. Several examples of JEcMnorliynchus angustatus from the intestine of a trout. 



T^atural size. 



10. One of the same (x 12 diam.). 



11. JEchinorliynchus nodulosus, from a small trout. Natural size. 



12. The same (x 12 diam.). 



13. Two eggs of -E". nodulosus, showing their peculiar form and circumscribed yelk 



contents (x 1000 diam.). 

 Figures 1 to 8 inclusive are from original sources (T. S. C), the remainder 

 ffom drawings by Mr. Busk. 



PLATE IX. 



1. Cyst from beneath the peritoneal surface of the intestine of a haddock. (Natu- 



ral size.) 



2. The same ruptured (x 4 diam.). 



3. Scolex of a Tetrarhynchus escaped from the ruptured cyst, and showing the 



invaginated head and body (x 4 diam.). 



4. The same, with the head and body drawn out. !N"atural size. 



5. Part of the scolex, exhibiting four narrow phylloid bothria, the body part of the 



so-called caudal vesicle, and, more particularly, the four armed proboscides, 

 two of which are partially protruded (x 20 diam.). 



6. One of the calcareous particles from the caudal vesicle (x 200 diam.). 



7. Section of a proboscis, showing the peculiar arrangement of the hooks 



and booklets. The figure marked e represents a series of delicate anasto- 

 mosing canals seen beneath the integument at the lower part of the body in 

 front of the caudal vesicle. 



These figures are original. — T. S. C. 



PLATE X. 



L Outline of the dissection of a young sun-fish {Orthagoriscus mo ?«), showing 

 several Tetrarliynchi lodged within cysts imbedded in the retractor muscles 

 of the anal fin. Reduced to one-sixth of the natural size. 



2. The so-called head, neck, subcervical enlargement, and upper part of the body 



of Tetrarhynchus rejptcms inclosed in its transparent sheath. Enlarged one- 

 third. 



3. Anterior fourth of the body of the same removed from its investing capsule. 



Natural size. 



