GASTEROPODA. 



87 



presents any peculiarities; and if operculated, whether the 

 operculum was pauci- or multi-spiral. 



The earlier describers of fossil univalves unhesitatingly 

 recognised many familiar recent genera, even in the older 

 rocks. But their Melanice were marine shells ; the supposed 

 Buccinum had no notch ; the Solarice were pearly ; the Neritce 

 assumed, when adult, the irregular aperture of Pileopsis ; the 

 NatAcce had non- spiral opercula; and the Maclurea was 

 figured upside down. 



Fig. 2G. 

 Palceozoic Univalves. 



i. Loxonema Lefeburei, Lev.; Carboniferous, Tournay. 



2. Macroclieilus Schlotheinii, d'Arcli.; Devonian, Eifel. 



3. Scoliostoma expansilabrum, Sdgr. ; Devonian, Nassau. 



4. Euomphalus sculptus, Sby. ; Wenloch Limestone, May Hill. 



5. Murcbisonia angulata, Ph. ; Devonian, Eifel. 



6. Porcellia Puzosi, Lev. ; Carboniferous, Tournay. 



7. Belleropbon bi-carinatus, Lev. ; Carboniferous, Tournay. 



8. Tubina armata, Ban*.; U. Silurian, Bohemia. 



9. Maclurea Peachii, Salter ; L. Silurian, Sutherland. 

 10. Conularia quadrisulcata, Sby. ; Carboniferous, Lanark. 



The more closely palaeozoic univalves are examined, so 

 much the more do they appear to differ from ordinary recent 

 types ; and the search for allied forms has to be conducted 

 amongst the rare and minute and least understood of recent 

 shells. 



