GASTEROPODA. 



71 



The earlier describers of fossil univalves unhesitatingly 

 recognised many familiar recent genera, even in the older 

 rocks. But their Melanim were marine shells ; the sup- 



Pi 



17. 



Palaeozoic Univalves. 



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



2. Macrochilus Schlotheimi, d'Arch. ; Devonian, Eifel. 



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



4. Euomphalus sculptus, Shy.; Wenlock Limestone, May Hill. 



5. Murchisonia angulati, Ph. ; Devonian, Eifel. 



6. Porcellia Puzosi, L6v. ; Carboniferous, Tournay. 



7. Bellerophon bi-carinatus, LeV. j Carboniferous, Tournay. 



8. Tubina annata, Barr. ; U. Silurian, Bohemia. 



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



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



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

 Neritce assumed, when adult, the irregular aperture of Pile- 

 opsis ; the Katiccc had non-spiral opercula ; and the Maclurea 

 was figured upside down. 



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. 



Ptcmpoda. — The fragile shells of Hyalea and Cleodora are 



