568 



MOLLUSCA 



PHYLÜM VI 



Family 6. Acteocinidae, novum {Tornatinidae Fischer). 



Radula unarmed. Tertiary and Eecent. 



Äcteocina Gray {Tornatina Adams) (Fig. 1065). Cylindrical, witli projecting 

 spire, and sinistral, tilted protoconcli. Columella bearing a single 

 fold. Tertiary and Eecent. 



Retusa Brown. Shell resembling Gylichna. Tertiary and 

 Recent. 



Volvula Adams (Volvulella Newton). 

 Fiisiform, the body whorl forming a point 

 above the sjiire. Eocene to Eecent. 



Fig. 1064. 



Bullaria ampulla 

 (Linn.). Pliocene ; Asti, 

 Italy. 



Fig. 1065. 



Äcteocina exerta 

 (Desh.). Oligocene ; 

 Jeurres, near Btampes 

 (after Deshayes). 



Family 7. Scaphandridae Fischer. 



Spire concealed ; radula with few teeth in a 

 row. Trias to Eecent. 



Scaphander 



Montf. (Fig. 1066). Shell sub-cylindrical, with epidermis, usnally 

 spirally striated. Body whorl of enormous capacity, much dilated 

 anteriorly. Columella spiral, leaving a false nmbilicus. Creta- 

 ceous to Eecent. 



Atys Montf. Cretaceous to Eecent. Diaphana Brown. Ter- 

 tiary and Eecent. Smaragdinella Adams. Eecent. 



Gylichna Loven {Bullinella Newton) (Fig. 1067). Small, 

 cylindrical, solid ; spire deeply perforated at 

 the summit ; body whorl covering all the 

 others. Aperture very narrow, outer margin 

 lower than the axis of the shell. Columella 

 thickened anteriorly ayd bearing a small plica- 

 tion ; often umbilicated. Trias to Eecent. 



Fig. 1066. 



Scaphander conic^is 

 Desh. Eocene ; Brack- 

 lesham, England. 



Family 8. Philinidae Fischer. 



Fig. 1067. 

 Cylielina conoidea 



Similar to Scaphandridae, hut shell internal, wdnheim, near^Tizey.' 



loosely coiled, punctate. Cretaceous to Eecent. 

 Philine Ascan. (Bullaea Lam.) (Fig. 1068). Cretaceous to Eecent. 



Family 9. Umbraculidae Pilsbry. 



Shell limpet-shaped, ivith low suh-central apex, and sharp, thin edges. Tertiary and 

 Eecent. 



Umhraculum Schum. {Umhrella Lam.). Shell orbicular, broad, 

 patelliform, ornamented exteriorly with concentric lines of growth ; 

 internal surface with concentrically undulating Striae. Eocene to 

 Eecent. 



Other families of Tectibranchiata, such as Aplysiidae, Pleuro- 

 hranchidae, etc., are represented in the Eecent fauna, but tlieir thin, 

 often membranous shells have not been found fossil. The supposed 

 Aplysias reported from the Pliocene by Philippi are flakes from the 

 interior of Pelecypod valves. 



Fig. 1068. 



Philine excavata 

 Deshayes. Eocene. 

 Calcaire Grossier ; 

 Grignon, near Paris. 



