CH. Vl] THE FRESH-WATER MUSSEL 1*75 



the action of cilia upwards into the stomach and thence 

 along the looped intestine, whose walls are ciliated 

 throughout, to the anus situated above and behind 

 the posterior adductor muscle. Into the cavity of the 

 stomach there discharge the ducts of the large digestive 



16 



17- 



18 



21 



Fig. 32. Right side of Anodonta mutabilis, dissected to show the viscera 

 x about 1. From Hatschek and Cori. 



1. Cerebro-pleural ganglion. 2. Cerebro-pedal commissure. 3. (Eso- 

 phagus. 4. Anterior retractor muscle. 5. Liver. 6. Stomach. 

 7. Aorta. 8. External opening of organ of Bojanus or nephridium. 

 9. Nephrostome or internal opening of the same. 10. Pericardium. 

 11. Right auricle. 12. Posterior end of ventricle passing into 



posterior aorta. 13. Rectum. 14. Glandular part of nephri- 

 dium. 15. Anus. 16. Opening of epibranchial chamber. 

 17. Ventral siphon. 18. Edge of shell. 19. Cerebro-visceral 

 commissure. 20. Intestine. 21. Foot. 22. Reproductive 

 organs. 23. Pedal ganglion of right side. 24. Mouth. 

 25. Opening of the reproductive organ. 



gland ("liver"), whose secretion has been shown by 

 Griffiths to effect the conversion of starch into dextrose 

 sugar, proteids to peptones, and to emulsify fats. It is 

 highly probable that this gland is also an important organ 



