1932 



ANNUAL REPORT, 1931 



27 



"* fisheries . 



Fig. 7. — Wardius zibethicus: os., Oral sucker; ph., Pharynx; vit., \'itellaria; gp., Genital 

 pore; t., Testes; ut., Uterus; sg., Shell gland; ov., Ovary; ps., Posterior sucker. (Original, 



