PLATE 23. 



Cross sections of Dondersia californioa. X 60 



Figs. 1, 2, 3, 5 correspond to lines A, B, C, D, fig. 4, pi. 5 (anterior enil). 



Fig. 4. Through anterior end of mid gut. 



Figs. 6, 9 are along hnes G, F of fig. 2, pi. 6 (posterior end). 



Fig. 7. Though middle of body. 



Fig. 8. Section through radula. X 555. 



