CLASS IV 



GASTROPODA 



523 



Eitphemus M'Coy (Fig. 849). Differs from BeUerophon in the revolving folds of 

 the inner lip. Carl)onifei'ous. 



Bucanopds Ulrich. Ordovician to Permian. 



JVarthia, Mogidia, and Stachella Waagen. Carboniferous. 



Pig. 849. 



E^iphemus nrii Fleming. Lower 

 Ciirboniferous : Bdiiibiugli. 



Fig. 850. 



Carinaropsis cymhula Hall. 

 Ordovician ; Kentucky. 



Family 8. Oarinaropsidae Ulrich and Scofield. 



Symmetrical, almost patelliform shells of not more than two volutions with greatly 

 expanded aperture luithin which is a broad concave septum. 



Garinaropsis Hall (Phragmostoma Hall, non Waagen) (Fig. 850). Dorsum carinate ; 

 slit band occasionally distinguishable. Ordovician and Silurian. 



Suborder B. RHIPIDOGLOSSA Troschel. 



{Scutibranchiata, Cuvier ; Zygobranchia and Diotocardia von Ihering.) 



Symmetrical and limpet-like or with spiral shells. Gills plume-like, two and sym- 

 metrical, or single. Eadula with several large plates or teeth in the median portion, and 

 excessively numerotis, crowded, narrow, hook-shaped teeth. Operculum often present. 



The Rhipidoglossa comj^rise both air-breathing and aquatic forms, and are divisible 

 into two series : Zygobranchia, in which two gills are developed, and the shell is 

 generally perforated at the apex or has a slit in the outer lip • and Anisobranchia, 

 with a single gill and generally unslit shell. 



Family 1. Haliotidae Fleming. 



Shell flattened, auriform, with wide aperture, and no operculum. Interior nacreotds, 

 with a row of perforations on the left outer margin. Marine. Cretaceous to Recent. 



Haliotis Linn. This, the solitary genus, occurs very rarely fossil except in the 

 Quaternary. 



Family 2. Pleurotomariidae d'Orbigny. 

 Shell spiral, sub-spherical, turbinate, conic, turreted or Planorboid, nacreous inter- 



Fin. 851. 



A, Fleurotoniaria {Ra}>histomelia) radians Wissni. Keuper ; St. Cassian, Tyrol. B, Pleurotomaria j 

 (firyptaenia) yolita Gqldf. Lower Lias ; GCippiugen, Wurteiuberg. 



