Fig 

 1. 



I' 





2. 







3. 







4. 







5. 







6, 



6 a. 





7, 



7 a, 



b. 



8, 



8 a, 



b. 



9, 



9 a, 



b, c. 



TAB. VIII. 



Pachyrisma grande, anterior view, jy. 79. 



„ posterior view, showing ligamental area, ji>. 79. 



„ hinge area of right valve, p. 79. 



„ hinge area of left valve, jo. 79. 



„ side view, p. 79. 



Unicardium parvulura, p. 74. 



,, varicosum, p. IS. 

 „ „ nucleus of ditto, p. 7S. 



„ impressum, j». 73. 



