VIII 



PHYLUM MOLLUSCOIDA 



363 



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

 whole canal is lined with ciliated epithelium. 



fil.si, 



The 



fil.si 



FIG. 290. A, body of IVXagellania lenticularis, removed from shell ; B, 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. HI. dorsal 

 mantle-lobe ; d. v. dorsal valve of shell ; gon 1 , gon' 2 . gonads ; ht. heart ; int. intestine ; ip, lp l . 

 lip; Ipli. lophophore ; IplJ-. its coiled process; inth. mouth; nph. in B, nephridium, in A, 

 nephridial aperture ; pd. peduncle ; pi. si. pallial sinuses ; s. seta? ; 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 



