APPENDIX. 245 
on than cover the bodies, which have a pair of lobes, 
around which vibrate minute cilia in such a manner 
as to give them an appearance of rotatory motion. 
Under a lens they may be seen moving about very 
actively in various positions, but always with the 
look of being moved by rapidly turning wheels. 
We should have been glad to witness the next 
step towards assuming their ultimate form, but 
were disappointed, as the embryos died. Fig. 
2 f is the tongue of a Nassa, from a_photo- 
graph by Dr. Kingsley. 
THE END. 
