351 



Fig. 92. — A, interior of right valve of Anodonta, showing the various 

 impressions produced by the muscles shown in B : ^i. /, hinge-line ;//. /. 

 pallial line. 



B, the animal removed from the shell and seen from the left side. 



a. ad, anterior adductor ; a. r, anterior retractor ; d. g, digestive gland, 

 seen through mantle ; ex. sph, exhalant siphon ; //, foot ; gl, gills, seen 

 through mantle ; in. sph, inhalant siphon ; kd, kidney, seen through 

 mantle ; k. 0, Keber's organ, seen through mantle ; in, mantle ; /. ad, 

 posterior adductor ; pc, pericardium, seen through mantle ; //. nt, pallial 

 muscles ; /. r, posterior retractor ; pre, protractor. 



(From Parker and Haswell's Zoology. ) 



short distance from it, is a delicate streak (//. /) caused by 

 the insertion into the shell of muscular fibres from the edge 

 of the mantle : the streak is hence called the pallial line. 



