480 J- F. ILLINGWORTH, The anatomy of Lucapina crenulata. 



Fig. 10. The same valve seen from the side of the ventricle. 3:1, 



Fig. 11. Median longitudinal section through the head. The rad- 

 ula is cut directly through its center; the posterior end is broken off. 

 The buccal sinus is outlined in color. 



Fig. 12. The left ctenidium turned back to reveal the position of 

 the osphradium. ^/g. 



Fig. 13. Dissection of the ocular tentacle, showing the eye with 

 its nerves. Greatly enlarged. 



Fig. 14. The otocysts, showing their relation to each other. Greatly 

 enlarged. 



Fig. 15. Cross-section of the pallio-pedal ganglia. Showing the 

 fusion of these two cords. This figure is taken from a series of sections, 

 DO one of which had all the nerves given off. Greatlj' enlarged. 



Plate 33. 



Large Figure. Central nerves system, the cords are all necessarily 

 enlarged. 2:1. 



Small Figure. A part of the nerves of the head region enlarged 

 to give a clearer idea of their branches. 



