PLATE V. 
Plethomytilus retortus, n. sp. (Page 52.) 
Fig. 
1. Specimen showing the expanded wing and recurved umbo. Lummaton. My 
Collection. 
RuTOTiA ELLiFTiCA, WMclhome, sp. (Page 55.) 
2. Left valve with very much expanded front wing. 2 a, posterior view. 
Lummaton. My Collection. 
3. Imperfect right valve of a very broad specimen. Wolborough. Museum of 
Practical Geology. 
4. Right valve of a flat shell with expanded front wing and very oblique umbo 
4 a, posterior view. Lummaton. My Collection. 
- 5. Right valve of a flat shell with very expanded front wing. Wolborough, 
Vicary Collection. 
6. Left valve of a convex shell with nearly equal wings. Lummaton. My 
Collection. 
7. Left valve of a convex shell with truncated anterior side. 7 a, upper view. 
Lummaton. My Collection. 
8. Left valve of a rather flat and transverse shell with truncated anterior side. 
8 a, posterior view. Lummaton. My Collection. 
9. Left valve of a broad convex shell with truncated anterior side. 9 a, anterior 
view. Wolborough. Vicary Collection. 
