4 WALTER K. FISHER, 



protrudes from the pallial cavity. There are two osphradia, one on 

 either side of the top of the head. The left, which is slightly the 



gzLZ*-^ _~—-- 



Fig. B. A cross section taken about the middle of the body to show the course 

 of the muscle fibres of the shell muscle, and the disposition of gland cells in sole. 

 Gl mucous cells in sole, Gn gonad, Med. 8 median blood sinus, L liver, R. K right 

 kidney, R. K' that portion on left side of the body, Y, Y' point where blood vessels of 

 gonad pass into membrane between gonad and right kidney, Z, Z' ventral line of at- 

 tachment of this membrane. 



larger, is in front of the base of the ctenidium, while the right oc- 

 cupies a similar position with respect to the anal opening. The large 



Fig. C. a) a few gland cells of foot enlarged, b) edge of anterior portion of foot 

 showing the abundance of gland cells. 



right ureter opens into the pallial cavity on the extreme right and 

 posterior side, while the anal aperture is just to the left of it. The 



