64 Transactions of the Royal Microscopical Society. 



been described by Dr. Cobbold, I have, therefore, no more to add 

 upon this head. 



This concludes what I have to say on the structure of Ascaris. 

 I have endeavoured as far as possible to avoid errors, and trust I 

 have done somewhat to put the anatomy of the Scolecida on a more 

 secure footing than it has hitherto possessed. 



DESCKIPTION OF PLATES. 

 Plate LXXV. 



Details of the Anatomy of Ascaris lumhricoides, 4'C. 



Fig. 3. — A fibre of muscle from the body wall x 120. 

 „ 4. — -The mouth seen in front, a, «, openings of water vessels x 30. 

 „ 5. — The pharjTix laid open, showing the ridges in the interior, x 10. 

 „ 6. — Anterior extremity of one of the pharyngeal ridges x 40. 

 „ 7. — Anterior extremity of the worm laid open, showing, b, 6, the water 



vabcular, and d,d, the nervous bands, with their ramifications and 



connections, x 15. 

 „ 8. — The external opening of one of the water vessels x 120. 

 „ 9.— One of the lips x 30. 



„ 10, — Cells from the upper portion of the testis x 750. 

 „ 11. — Cells from the middle portion of the testis x 500. 

 „ 12. — Cells from the duct of the testis x 500. 



Plate LXXVI. 



Details of Anatomy of Ascaris lumhricoides. 



Fig. 1. — Half a transverse section, made about two inches from the head, x 20, 

 showing, o, external layer of integument; b, cellular layer; c, 

 muscular layer ; d, lateral nerve-band ; e, transverse water-vessels 

 bearing vesicles {appendices nouricieres) ; /, alimentary canal ; g, 

 dorsal water vascular trunk x 20. 



„ 2. — A portion of the dorsal trunk, with transverse vessels, vesicles, and 

 pseudo-ha?mal vessels, detached from the other structures, x 25. 



„ 3. — A portion of the testis, with pseudo-haemal vessels ramifying upon 

 it, X 60. 



„ 4. — A transverse section of one of the lateral bands x 40. 



„ 5. — A portion of one of the lateral bands, x 25. 



„ G. — Ganglion corpuscles from the same x 500. 



„ 7. — A budding yelk from the lower part of the ovary x 200. 



„ 8. — Three yelks from the upper part of the ovary x 200. 



„ 9. — A budding yelk, from the lower extremity of the ovary, dividing into 

 two, X 200. 



