510 TROCEEDINGS OF THE ACADEMY OF [AugUSt, 



structures in C. calceola, but it was found to be present in each of 

 the fifty specimens of C. vitrea examined on this point. The 

 oesophagus leads directly backward into the visceral mass, where it 

 joins the relatively voluminous stomach provided with five large 

 and several small teeth. The intestine makes one turn on the 

 ventral surface of the stomach and opens into the mantle cavity 

 shghtly to the left of the median line. The remainder of t the 

 visceral mass is composed of the large liver and the gonad, which 

 has the form of a thin sheet investing the surface of the visceral 

 mass except at its forward extremity, where the albumen 'gland 

 and seminal receptacle are situated. 



Cymbulioj)sis vitrea, ventral view, natural size. C, casque or "shell ;" 

 /., foot or fin ; k., kidney within mantle cavity represented by stippled line ; 

 tt., nucleus or visceral mass, showing termination of intestine and pigmented 

 cap ; p., pallial gland. 



The mantle cavity is placed on the ventral side of Ciimbuliopsis, 

 and anterior to the visceral mass a portion of the bounding epithe- 

 lium is modified into the pallial gland. This is crossed by one 

 complete and two incomplete transparent bands. Peck states that 

 the pallial gland is " almost symmetrical in this genus, being 

 twisted somewhat to the right, but the asymmetry was not marked." 



In C. vitrea the asymmetry is not especially apparent, but it is 

 twisted in the reverse direction to that described and figured bv 



