312 MOLLUSCS. 



DIAGRAM XV. 

 The Fresh-water Mussel. 



The figure of a dissected Anodonta (after Rankin) shows the following 

 structures :— The inhalent aperture (inh.), the exhalent aperture (,exh.\ 

 the mouth (m.), the gills [g.], the protruded foot, the anterior adductor 

 (a. a.), the posterior adductor {p. a.), the retractor muscles of the foot, 

 the cerebro-pleural ganglia above the mouth, the pedals (/.) in the foot, 

 the viscerals {v.) below the posterior adductor, the labial palps (/./.), 

 the stomach (st.), the " liver " (/), the coils of the gut in the foot, the 

 passage of the gut through the ventricle {v.), the rectum (r.), the kidney 

 (k.), the reproductive organs (rep. ) in the foot. 



The cross-section (after Vogt and Yung) shows the external shell, the 

 dorsal ligament (/.), the dorsal line of the maiitle (m.), the pericardium 

 {p. c), the ventricle (v.), the enclosed gut {g.), the auricles (a.), the 

 vena cava (v. c), the sac of the kidney («.), the gland of the kidney 

 (k.), the nerves (».) connecting cerebro-pleurals and viscerals, the gut 

 (g.) in the foot {/.), the gills between foot and mantle. 



To the left is the nervous system [nerv.) with cerebro-pleurals (c. p.), 

 pedals (/.), and viscerals [v.). 



To the right is a Glochidium (from Balfour), showing the shell [sh. ) 

 with its spines (s.), the adductor muscle (ad.), the byssus (by.). 



