486 MOLLUSCA SUB-KINGDOM VI 
Family 2. Ringiculidae. 
Inoperculate forms resembling Actaeonidae in having columellar folds. Cretaceous 
to Recent. 
Cinulia, Gray (Fig. 1012). Globose, inflated, spirally grooved or punctate. Spire 
short ; aperture crescentic ; outer lp reflected and thickened. Columella and inner 
lip with numerous transverse folds. Cretaceous. 
Sub-genera: Avellana, Ringinella, VOrb. ; Eriptycha, Meek ; Fortisia, Bayan. Eocene. 
Ringicula, Desh. (Fig. 1013). Small, ovoid to globose, thick-shelled, with mamil- 
lated protoconch. Spire short; body whorl large, usually smooth. Aperture canali- 
A B C 
muchas 
avutiniernt 
weumeaue 
never 





Fic. 1012. Fic. 1013. 
A, Cinulia (Avellana) incrassata, Mant. sp. Gault; Perte Rinyicula Hoernesi, 
du Rhone. B, C. (Ringinella) lachryma, Mich. Gault; Seguenza. Miocene ; 
Folkestone, England. (C, C. (Zriptycha) decurtata, Zekeli. Steinabrunn, near 
Turonian. Gosau, Austria. Vienna. 
culate posteriorly, excavated anteriorly. Columellar border thick and callous; the 
columella arched, and furnished with from two to four plications. Outer margin 
usually very thick, reflected, and occasionally denticulated within. Cretaceous to 
Recent. 
Pugnus, Hedley. Cylindrical, with sunken spire. Recent. 
Family 3. Akeratidae.  Pilsbry. 
Shell oval or cylindrical, thin and fragile, the spire low or concealed. Tertiary and 
Recent. 
Akera, Miiller (Fig. 1014). Thin-shelled, flexible, with exposed, truncated spire. 
Whorls separated from one another by deep sutures. Sutures 
deep and prominent; outer lip separated from the spire. 
Eocene to Recent. 
Haminea, Leach. Oval, thin-shelled, brittle; the spire 
concealed. Tertiary and Recent. 

MIG. 10 can . . . : 
ee Family 4. Hydatinidae. Pilsbry. 
Akera striatella, Lam. i 
Oligocene ; Castel Goimberto, 
“sate WU. Globose or oval, with exposed, nearly level spire and tilted 
nucleus. Jura to Recent. 
Hydatina, Leach, Schum. Jura to Recent. Aplustrwm, Schum.; Micromelo, 
Pilsbry. Recent. 
Family 5. Bullidae. Pilsbry (emend.). 
Shell oval or sub-globose, involute, smooth. Spire sunken and concealed. Apertwre 
long, rounded anteriorly ; outer lip sharp. Marine. Jura to Recent. 
