TAB. IV. 



X 



h X 



i X 



i' X 



J X 



j' X 



Fig. 10. Ci/lhereis quadrilatera, continued. 



50 Adult, perfect, anterior aspect . . Gault. 



50 Immature, left valve, outside 



50 Immature, left valve, outside 



50 Immature, perfect, dorsal aspect . 



50 Young, right valve, outside 



50 Young, perfect, dorsal aspect . . Detritus. 



Fig. 11. Cythereis ciliata. 



a X 50 Adult, left valve, outside . . . Detritus 



/^ X 50 Adult, perfect, placed obliqueh^ left valve 



upwards . . . ,, 



c X 50 Adult, })erfect, dorsal aspect 



(1 X 50 Adult, perfect, ventral aspect 



<' X 50 Adult, perfect, anterior aspect 



/ X 50 Immature, left valve, outside 



(J X 50 Young, left valve, outside . 



g X 50 Young, perfect, dorsal aspect 



// X 50 Young, left valve, outside . 



// X 50 Young, perfect, dorsal aspect 



Gault. 



Folkstone. 



Charing. 



Charing. 



Folkstone. 



Detritus. Charing. 



