652 JAMES L. KELLOGG 
from which position it drops to the mantle. Figure 17 is a view 
of the region about one of the mantle vortices, seen from above. 
Except in minor details which a comparison of figures will reveal, 
the mantle ciliation is like that of Mya. 
ee 
eee = 
<—— 
Fig. 18 Mytilus edulis; aa, anterior adductor; bm, byssus muscles; bs, byssus; 
f, foot; p, anterior palp; sm, siphon membrane; x, meeting of currents on mantle 
edge; v, divergence of currents. 
Fig. 19 Mytilus edulis; view of palps from below; ap, anterior palp; 7g, inner 
demibranch of gill; og, outer demibranch of gill; pg, proximal oral groove; pp, 
posterior palp. 
