PLATE XX. 



Pal^opteeia parvula (page 181). 



Figure 1. Side view of a cast of the interior of a small right valve, twice the natural 

 size. 

 tr 2. Outline of the cardinal region of the cast cf another right valve, six times 

 the natural size, and shewing the impressions made by the hinge 

 teeth. 

 11 3. Side view of a cast of the interior of a large left valve supposed to be re- 

 ferable to this species, twice the natural size. 



MODIOLOPSIS ANGUSTIFRONS (page 183). 



Figure 4. Side view of the type and only known specimen of this species, shewing 

 the left valve. 



Orthodesma affine (page 184). 



Figure 5. Side view of the specimen described, shewing the right valve. 



Clinopistha antiqda (page 185). 



Figure 6. Side view of the only specimen known to the writer. 



Rhytimya recta (page 186). 



Figure 7. Side view of a cast of the interior of a right valve of this species. 



Edmondia (?) VET0STA (page 187). 



Figure 8. Side view of a specimen of this species, twice the natural size. 



Pleurotomaria Stokesiana (page 190). 



Figure 9. Dorsal view of the most perfect specimen collected, which is a cast of the 

 interior of the shell, twice the natural size. 

 M 9a. Basal view of the same. 



Pleurotomaria maegaritoides (page 190). 



Figure 10. Dorsal view of a gutta percha squeeze of a natural mould of the exterior of 

 a shell of this species, three times the natural size. 



Maclueea (Maclueina) Manitobensis (page 194). 



Figure 11. View of a specimen from Little Black Island, with most o{ the test pre- 

 served on the convex side. 



