253 INTRODUCTION. 



Fig. VI. Genitalia. 1. Testicle; 2. epididymis ; 2.* vas deferens ; 

 3. accessory gland of epididymis; 4. prostate; 5. penis; 6. retractor 

 of do.; 7. ovary; 8. oviduct; 9. genital bladder; 10. vagina; II. 

 cloaca. 



Figs. VII. — IX. Attditory apparatus of H. pulchella. 



Fig. VII. Inferior ganglia of the sub-oesophageal mass, highly 

 magnified, with the auditory vesicles attached. 



Fig. VIII. Side view of one of the auditory vesicles. 

 Fig. IX. Otoconites, very highly magnified. 



PLATE X. 



Figs. I. — III. H. exoleta. 



Fig. I. Digestive apparatus. 1. Buccal body; 2. lingual pouch; 

 3. retractor of buccal body ; 4. stomach ; 5. intestine ; 6. salivary gland ; 



7. ducts of do.; 8. hepatic ducts. 



Fig. II. Genitalia. Same references as Fig. VI. PI. IX. ; 2.** glan- 

 dular commencement of vas deferens. 



Fig, III. Penis laid open. 1. Longitudinal folds ; 2. vas deferens; 

 3. valvular folds ; 4. retractor of penis ; 5. vagina; 6. orifice of do. 



Figs. IV. V. H. elevata. 



Fig. IV. Viscera dissected apart. 1. Buccal body ; 2. oesophagus; 

 3. stomach; 4. intestine; 5 rectum; 6. anus; 7. salivary gland; 



8. liver; 9. testicle; 10. epididymis; 11. accessory gland of do. ; 10.* 

 vas deferens ; 12. prostate; 13. penis; 14. retractor of do. ; 15. ovary; 

 16. oviduct; 17. genital bladder; 18. pulmonary chamber; 19. pul- 

 monary vein; 20. heart; 21. renal organ ; 22. duct of do. ; 23. pulmo- 

 nary orifice ; 24. supra-, 25. sub-oesophageal, and 26. stomato-gastric 

 ganglia. 



Fig. V. Penis laid open. 1. Longitudinal folds of interior ; 2. vas 

 deferens; 3. retractor of jjenis. 



PLATE XI. 



Figs. I. — IV. H. Sayi. 



Fig. I- Digestive apparatus. 1. Buccal body; 2. retractor of do ; 

 3. lingual pouch ; 4. oesophagus ; 5 stomach; 6. intestine; 7. salivary 

 gland ; 8. salivary ducts j 9. hepatic ducts. 



