316 



.MOLl.L'SCA 



The anus is medial, and n;du and left of it are the openings of the neph- 

 ridia and sexual organs. The sexes are separate, the gonads unpaired, 

 while, eorresponding to the paired arrangement of the gills, there are two 

 aurieles to the heart. 7V.;e/;.v<,'cTwe«,* Aiiiinil.i/^ C^m'/i/.'.-': .■/"".* 



Fig. ^i;. — L liihii: squamosum, dorsal view lafler llallcrK .l,lhe entire animal- 

 B. after removal of shell and viscera; <i, anus; c", brain; K, clenidia; o, moulli; F, ped;il 

 nerve cord; p!. plcurovisccral nerve cord. 



^^ 



xP 



Fig. 310. 



l"ie.. ;i7 



Fig. 310. — Eve and a'Sthetes of Acanthol^lciira spiiili^cr (after MosclcyV ii, 

 macra:stlicle; />, mier;esthete; /', calcareous cornea , i,\ lens;/;, iris; A', pii^menled capsule; 

 n, p, ner\'es; r, retina. 



Fn;. 317. — Nronit-iud carinata, ventral and side views (after TulberL;). »;, anterior; 

 b, posterior; r, \'entral j;rt)0\'e. 



Siih Class II. Solcuoc,(islrcs [Aplaciiphora) 



Wornilike forms widionl :i shell (occurs in the larva of Di'iiihrsiii); instead of 

 a fool there is a lonL;iludin:\l \enlr;d eili;iled groove; the raduh\ ukiv he lost; in 

 Coiichodcniia it bears but a sinj^de tooth. The gills are either small or wanting. 

 The usually hermaphrodite animals haw the gon;ids emplving into Ihc peri- 

 cardivmi and thence by the paired nephridia (?). Marine, li\'ing in oo/.e or sand. 

 ChalodcrxiaA Ncomniin, Dmidcrsia. 



