PHYLUM MOLLUSCOIDA 



:m 



into it by a duct, is a large, branched digestive gland (d. gl). The 

 whole canal is lined with ciliated epithelium. 



Fk;. 290.— A, body of Wlagellania lenticularis, removed from shell ; 13, sagittal section of 

 the entire animal. Both semi-diagrammatic, the lophophore being represented as of smaller 

 proportional size than in the actual animal (cf. Fig. 291). d. gl. digestive gland ; d. m. dorsal 

 mantle-lobe ; d. v. dorsal valve of shell ; gonX, gon'*. gonads ; ht. heart ; int. intestine ; Ip, Ip 1 . 

 lip; Iph. lophophore ; I phi. its coiled process; mth. mouth; nph. in B, nephridium, in A, 

 nephridial aperture ; pd. peduncle ; pi. «'. pallial sinuses ; *. setie ; st. stomach ; v. m. ventral 

 lobe of mantle ; v. v. ventral valve of shell. 



The body- wall consists externally of an epidermis formed of a 

 single layer of cells, then of a layer of connective tissue, of a 



