TAB. IX. 



Fig. 

 la — h. Aturia zic-zac (English specimens), p. 52. 



a. Side view of the typical form, from Highgate. 



b. Front view 



do. 



do. 



c. Side view 



do. 



from Sheppy. 



d. Front view 



do. 



do. 



e. Side view 



do. 



from Bracklesham Bay 



/. Front view 



do. 



do. 



g. Side view of the compressed variety (j3), from Chalk Farm. 

 h. Front view do. do. 



2 and 3. Aturia zic-zac (Dax specimens). 



2. Oblique view, showing the construction of the siphuncle. 



3. Front view, showing the form of the septum. 



