SUB-ORDER A TECTIBRANCHIATA 485 
Adelactaeon, Cossm. (Myonia, Adams). Protoconch with sinistral nucleus ; not very 
large. Whorls decussated by fine striae, growth-lines inconspicuous. Columella 
slightly excavated, and carrying a small but well-marked plication. 
Miocene of France and Germany, and Recent. 
Actaeonina, VOrb. (Orthostoma, Desh.), (Figs. 1006, 1007). 
Shell ovoid to fusiform, usually smooth, rarely spirally striated. 

Fic. 1007. 
Actaeonina myosotis, 
Buy. Coral-Rag; St. 
Mihiel, Meuse. 2/1 
(after Buvignier). 

Fic. 1008. 
Cylindrites  acutus, 
Fia. 1006. 
; “ ‘IG ‘ 
Actaeonina Dormoi- Sowb. sp. Great Fic. 1009. 
siand, V@Orb. Coral-Rag ; Oolite; Minchin- Actaeonella gigantea, Sowb. Turonian; Griin- 
Valfin, Ain. hainpton, England. bach, Lower Austria. 
Spire conical, body whorl very large, narrowing toward the base. Columella straight, 
without folds. Outer lip sharp. Carboniferous to Recent. 
Sub-genera : Euconactacon, Conactaeon, Meek. Lias. Douvilleia, Bayle. Tertiary. 
Cylindrites, Fer. (Fig. 1008). Cylindrical-ovoid with short spire. Columella 
with an anterior fold. Trias to Cretaceous. 
Bullina, Fer. Jura to Recent. Cylindro- 
hullina, v. Ammon. ‘Trias, Lias. Htallonia, 
Desh. Jura and Tertiary. Bullinula, Beck. 
Jura to Recent. 
Actaeonella, WOrb. (Figs. 1009 - 1011). 
Thick-shelled, inflated, smooth. Spire short ; 
columella thickened anteriorly, with three 
sharp folds. Very profuse in the Middle and 
Upper Cretaceous; maximum distribution in 
the Hippurite Limestone of the Alps. 
Sub- genus: Volvulina, Stol. (Fig. 1011). 
Like the preceding, but with insunken spire. 

Cretaceous. Fic. 1010. Fic. 1011. 
Actaeonella voluta, Actaeonella (Volvu- 
r . : : : : Goldf. Turonian; lina) laevis, Sowb. 
7 are 5 nT RE r . . 
Volvaria, Lam. Cylindrical, with in- Gams, Styria. "| iaronian 5 Gosau, 
volute, concealed spire. Surface usually 
spirally striated ; aperture narrow ; columella with four anterior plications. Eocene. 
