532 



MOLLUSCA 



PHYLUM VI 



Gibbula Risso (Figs. 885, 886). Turbinate or low conical, umbilicate, and with 

 rounded aperture. Tertiary and Recent. 



Fig. 887. 



Calliostoyna semi- 

 punctatum Miinst. 

 Keuper ; St. Cas- 

 sian, Tyrol. 2/j. 



Fic. 8S8. 



Callinstoma aequalis 

 Bnv. Coral-Rag ; St. 

 Mihiel, Meuse. 



Fig. 889. 



LeviHeUa conica (d'Orb.). 

 Middle Lias ; May, Cal- 

 vados. 



Fig. 890. 



Solariella peregrina 

 (Libassi). Pliocene ; Or- 

 ciano, Tuscany. 



Margarites margarifula 

 Mer. Oligocene ; Weinlieim, 

 near Alzey, Baden. 



Galliostoma Swains. (Ziziphinus Gray) (Figs. 887, 888). Conical, with j^eripheral 



keel and flattened base. Trias to Recent. 



Other genera are Cantharidus Montfort ; Lewisiella 

 Stol. (Fig. 889); Tegnla Lesson; Solariella Wood 

 (Fig. 890) ; Margarites Leach (Fig. 891) ; Danilia Brus. 

 (Fig. 892) ; Gamitia Gray, and many others. Most of 

 tliese have a more or less extensive Tertiary history. 



Family 12. Umboniidae Adams. 



Fir; 802 



Shell small, usually depressed discoidal, smooth and 

 Danilia clathrata(Eta,l\.). Coral-Raff: 7 , -.i /. • i ± • 7 -,7 , 



Vaifin, Ain. 2/j. lustrous, or loitn jine spiral striae, ana without nacreous 



layer. Outer lip sharp, peristome discontinuous. Um- 

 bilicus often concealed by a callus; operculum horny. Silurian to Recent. 



Allied to the Recent genera Umbonium Link (Botella Lam.), Tsanda Adams, 



Fig. 893. 



Chryi^ontoma 

 ac)mm(d'Orb.). 

 Middle Jura ; 

 Balin, near 

 Cracow. 



Fig. 894. 



Teinostmna rotellaa- 

 forniis Desk. Calcaire 

 Grossier ; Grignon, 

 near Paris. 



Fig. 895. 



Hdicocryptiis 2'msillus (Roem.). Coral- 

 Rag ; Lindeuer Berg, near Hannover. 



iFiG. 89(3. 



Adeorhis tricostatus 

 Desh. Middle Eocene 

 (Auversien) ; Auvers, 

 Seine-et-Oise. 



etc., are a number of fossil forms, such as Pycnomphalus Lindstriira, from the 

 Silurian and Devonian ; Anomphalus Meek and Worthen, and Botellina de Koninck, 

 from the Carboniferous ; Ghrysostoma Swaiuson (Fig. 893), from the Jura, and otliers, 

 Avhich are probably the ancestors of the Umboniidae. 



Whether the genera Teinostmna (Fig. 894) and Vitrinella Adams, together with 

 their fossil allies from the Carboniferous onward, are rightly assigned to this group, is 

 doubtful. Helicocryptus d'Orb. (Fig. 895), from the Jura and Cretaceous, is similar to 

 Vitrinella. Gyclostrema Marryat, comprisiug small, lustrous shells, and the spirally 

 striated ones known as Adeorbis S. Woodw. (Fig. 896), present some resemblances to 

 the Umboniidae ; but, according to Fischer, they form separate families. All of these 

 genera have fossil representatives in the Tertiary. 



