546 



MOLLUSCA 



PHYLUM VI 



lip arcuate, generally tliickened ; aperture somewhat notched or effuse at the base. 



Dogger to Recent ; mainly 

 ^ ^ Tertiary. 



Bissoa Frem. (Fig. 959). 

 Turreted, transversely riljbed 

 or cancellated, aperture entire 

 l)elow. Jura to Recent. 



Fio. 958. 



A, Rissoina amocna Zitt. Titlion- 

 ian ; Stramberg, Moravia. B, R. 

 Ue<'Uf:sata Montf. Miocene ; Steina- 

 brunn, near Vienna. 



Fici. 9:J9. 



A, Rissoa turhinata (Lain.). 

 Oligocene ; Weinheini, near 

 Alzey. /.', R. (Alr<inia) mon- 

 iagui Payr. Miocene ; Steina- 

 brunn, near Vienna. 



Family 12. Turritellidae 

 Gray. 



Shell turreted, with liigh 

 acuminate spire. Whorls numerous, usually spirally ribbed or striated. Aperture oval, 

 round or quadrangular, sometimes ivith faint anterior canal. Outer lip thin, peristome 

 discontinuous. Operculum horny, muUispiral. Marine. Trias to Recent. 



Turritella Lam. (Figs. 960, 961). Spire very high ; aperture oval or rounded 



quadrilateral ; outer lij) thin, excavated behind, and 

 slightly jjroduced in front. Trias to Recent ; maximum 

 in Tertiary. The older Mesozoic species are usually 

 small. 



Fic. 960. 



A, Turritella tnrris Bast. ('/'. 

 terelira Ziet. non Linn.). Miocene 

 Molasse ; Enningen, near Ulni. 

 B, T. irnhricatarin Lam. Cal- 

 caife Grossier ; Grignon, near 

 Paris. 



Subgenera : Mesalia Gray (Fig. 961 

 but aperture with shallow canal, and 

 Tertiary to Recent. 



Protoma Baird 

 {Proto p.p. Defr. ). 

 Aperture oval, an- 

 teriorly with canal- 

 like contraction, 

 which is surrounded 

 externally by a thick 

 swelling. Tertiary 

 and Recent. P. 

 cathedralis Brgt. 



Glauco)iia Gie- 

 bel (Omphalia 

 Zekeli ; Cassiope 

 Cocp) (Fig. 962). 

 Thick-shelled, coni- 

 cal or turreted, 

 narrowly umhili- 



Like the last, 

 twisted inner lip. 



Fiii. 9(3L 



TurritcUa {Mesalia) 

 multisulcata Lam. 

 Eocene ; Calcaire 

 Grossier ; Grignon, 

 near Pari.s. 



Glauconia kefersteini 

 Goldf. Middle Cre- 

 taceous ; Dreistiitten, 

 near W'iener-Nenst. 



cate. Whorls 



spirally ribbed, rarely smooth. Aperture oval, with faint canal ; outer lii? ^\ith 

 anterior and median emargination. Abundant in the Cretaceous. 



Family 13. Vermiculariidae, novum. {Vermetidae Adams). 



Shell tubular, the earlier whorls spiral, the later ones irregularly twisted, free or 

 attached. Aperture round; operculum horny, sometimes icanting. Carboniferous to 

 Recent. 



Some fossil Vermetidae are liable to be mistaken for Serpulidae, but differ from 

 them neverlheless in the structure of the shell and spiral protoconch. The determina- 

 tion of the few Paleozoic and Mesozoic forms is uncertain. 



Vermicularia Lam. {Vermetus Daudin) (Figs. 963, 964). Shell usually attached, 

 irregularly tubular, internally vitreous, and often with septa. Carboniferous (?) to 

 Recent. Abundant in the Tertiary, 



