448 MOLLUSCA 
round, ornamented with raised longitudinal keels, 
internally, conical externally, multispiral. 
abundant in Silurian. 
Cyclonema, Hall (Fig. 818). 

SEUETEAN 
7? 7 
(CEK 
tS 
C7) 
y és «ee 

Fig, 818, 



GENK 


SUB-KINGDOM VI 
Operculum extremely thick, flat 
Ordovician to Carboniferous ; especially 
Turbinate ; whorls inflated and ornamented with 

» aie ry rs Q) 
Cyclonema dilix, Fic. 819 Fic. 820. 
Conrad. Ordo- : ene Astralium (Uvanilla) Damon, 
vician ; Cincinnati, Astralium (Bolma) rugosum, Linn. Pliocene ; Laube. Keuper; St. Cassian, 
Ohio. Pienza, Tuscany. Shell and operculum. , Tyrol. 
fine spiral striae. Aperture rounded, peristome discontinuous. 
flat internally, externally with spiral flutings. 
Astraliwm, Link. (Figs. 819, 820). 
rough, often spinose, and usually keeled. 
with disconnected margin. 
spirally coiled, and 
nucleus. 

poma, Lithopoma, 
Fic. $22. 

Collonia modesta, 
Fuchs. Oligocene; ; 
Monte Grumi, near conical 2 
fae Gombert? renban caleareous, thick, 
flat internally, extern- 
ally convex, multispiral, with sub-central nucleus. Silurian (?) 
to Recent. 
Fic. 821. 
Turbo (Ninella) Parkinsoni, 
Bast. Oligocene; Dax, near 
Bordeaux. 
Sub-genera: Sarmaticus, Ninella (Fig. 821); Modelia, Callopoma, 
Gray ; Senectus, Humphr. ; Batillus, Schum., ete. 
Collonia, Gray (Fig. 822). 
thin calcareous layer disposed in a spiral rib. 
Like Turbo, but operculum with 
Eocene to Recent. 
Family 8. Phasianellidae. Troschel. 
Shell elongated, oval, thin, smooth, lustrous, porcellanous, not 
nacreous internally, without wmbilicus. Body whorl large, with 
oval aperture. Operculum calcareous, convex externally. Devonian 
to Recent. 
Phasianella, Lam. (Phasianus,  Montf.), (Fig. 823). With 
the characters of the family. Cretaceous to Recent ; perhaps also 
Turbo, Linn. (Fig. 821). 
aperture nearly circular. 
Operculum conical, 
Ordovician to Devonian. 
Turbinate ; whorls 
Aperture depressed, 
Base more or less flattened ; 
operculum calcareous, thick, flat internally, 
with 
Trias to Recent. 
very eccentric 
Sub-genera : Bolma, Risso (Fig. 819) ; Pachy- 
Uvanilla (Fig. 820), Guil- 
Jordia, Gray ; Calcar, Montfort, ete. 
Turbinate to 
Oper- 

Fic. $28, 
Phasianella Gosauica, 
Zekeli. Turonian ; 
Gosau, Austria, 
Palaeozoic. 
