566 



MOLLUSCA 



PHYLUM VI 



Columella thick, witli one strong, spiral, sliglitly oblique, plication. Upper Cretaceous 



to Recent. 



Ädelactaeon Cossm. {Myonia Adams). Sliell witli siiiistral protoconcli, tlie latter 

 not very large. Wliorls decussated by fine Striae, growtb-lines 

 inconspiciious. Columella sliglitly excavated, and carrying a 

 small but well-marked plication. Miocene of France and Ger- 

 many, and Recent. 



■((II 



Fio. 1056. 



Actaeonina myosotis 

 Buv. Coral-Rag; St. 

 Miliiel, Meuse. 2/j 

 (after Buvignier). 



Fig. 1055. 



Actaeonina do'nnoisiana 

 d'Orb. Coral-Rag; Val- 

 fln, Ain. 



Cylindrites acutus 

 (Sowerby). Great 

 Oolite; Minchin- 

 hanipton, England. 



Actaeonella gigantea Sowb. Turonian 

 Grünbach, Lower Austria. 



Actaeonina d'Orb. {Orthostoma Desb.) (Figs. 1055, 1056). Shell ovoid to fusiform. 

 usually smootb, rarely spirally striated. Spire conical, body whorl very large, 

 narrowing toward the base. Columella straigbt, witliout folds. 

 Outer lip sharp. Carboniferous to Recent. 



Subgenera : jEuconactaeon, Conactaeon Meek. 

 Lias. Douvilleia Bayle. Tertiary. 



Fio. 1059. 



Actaeonella voluta 

 Goldf. Turonian; 

 Garns, Styria. 



Fitt. 1060. 



Actaeonella (Volvu- 



Fdr. (Fig. 1057). Cylindrical- 

 ovoid with short spire. Columella witli an 

 anterior fold. Trias to Cretaceous. 



Bullina Fer. Jura to Recent. Gylindro- 

 hullina v. Amnion, Trias and Lias. Etallonia 

 Desh. Jura and Tertiary. Bullinula Beck. 

 Jura to Recent. 



Actaeonella d'Orb. (Figs. 1058 - 1060). 

 Thick - shelled, inflated, smooth. Spire short; 

 columella thickened anteriorly, with three 

 Sharp folds. Very profuse in the Middle and 



Hna) laevis Sowb. Upper Cretaceous ; maximum distribution in 



the Hippurite Limestone of the Alps. 



Subgenus : Volvulina Stol. (Fig. 1060). Like the preceding, but with insunken spire. 

 Cretaceous. 



Volvaria Lam. Cylindrical, with involute, concealed spire. Surface usually 

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

 Ovulactaeon Dali. Similar in form to Gypraea, but witliout plications. Recent. 



