650 JAMES L. KELLOGG 
+ © | \ 
| | 
Nea 
SIA 
= be NX \ wii ‘iN 
tye < ~ eau 
iy e > — - 
Fig. 18 Mya arenaria; ciliation of visceral mass; f, foot; s, siphon; v, vortex; 
vms, visceral mass. 
Fig. 14 Mya arenaria; ciliation of mantle; fo, foot opening in mantle edge; 
me, mantle edge; s, siphon; v, vortex. 
