SUH-ORDER A 



TECTIBRAXCHIATA 



485 



Adelactaeon, Cossm. (Myonia, Adanis). Protocondi with sini.-tral nucleus ; not very 

 Whorls decussated by fine stria.-, growth- lines inconspicuous. Coluinclla 

 slightly excavatfl, ami < arrving a small but well-marked plication. 

 Miocene of Franrt- ami < ii-nnany, and Rorriit. 



Actaeonina, d'Orb. (Orthostoma, Desk), (Figs. 1006, 1007). 

 Slii-11 ovoid to fusiform, usually smooth, rarely spirally striated. 



PlO. 1007. 



Actaeonina myosotis, 

 Buv. Coral-Rag; St. 

 Miliifl. Mruse. 2 /i 

 (after Buvignier). 



FIG. 1006. 



Actaeonina Dormoi- 

 siana, d'Orb. Coral-Rag; 

 Valtiu, Aiii. 



FIG. 1008. 



Cylindrites acutus, 

 Sowb. sp. Great 

 Oolite; Minchin- 

 hainpton, England. 



FIG. 1009. 



Actcteonella (jitjantea, Sowb. Turonian ; Griin- 

 bach, I^ower Austria. 



Spire conical, body whorl very large, narrowing toward the base. Columella straight, 

 without folds. Outer lip sharp. Carboniferous to Eecent. 



Sub-genera : Euconactaeon, 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. Etallonia, 

 Desh. Jura and Tertiary. Bullinula, Beck. 

 Jura to Recent. 



Actaeonella, d'Orb. (Figs. 1009-1011). 

 Thick -shelled, inflated, smooth. Spire short ; 

 columella thickened anteriorly, 'vith 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. 



F>:. 1011. 



..... Ian; 



Volvaria, Lam. Cylindrical, with in- 

 volute, concealed spire. Surface usually 

 spirally striated ; aperture narrow ; columella with four anterior plications. 



Eocene. 



