564 



BJORN A. AFZELIUS 



Fu;. 7. Transverse section through ciHa from mussel gill {Alyti/ns edulis). The 

 arrows point to cilia where part of the "top plate" has been included. The 9 + 2 

 filaments seem to fuse in the top plate in the distal part of the cilium. Magnifica- 

 tion 54 000 X . 



Fig. 8. Another transverse section through cilia from mussel gill (Mytilus 

 edulis). This type of cilium diflfers from that in the preceding figure by having no 

 top plate. The nine peripheral filaments are single in their distal tips and do not 

 join with each other. Note here also the asymmetrical position of the two inner 

 filaments in most of the cilia. Magnification 68 000 x . 



