546 



MOLLUSCA 



phylü!m vi 



lip arcuate, generally tliickened 



aperture somewliat iiotclied or effuse at tlie base. 

 Dogger to Recent ; mainly 

 Tertiary. 



Rissoa Frem. (Fig. 959). 

 Turreted, transversely ribbed 

 or cancellated, aperture eutire 

 below. Jura to Recent. 



FiCx. 958. 

 A, Rlssoina amoena Zitt. Tithon- 

 ian ; Stramberg, Moravia. B, B. 

 (Ifcussata Montf. Miocene; Steina- 

 brunn, near Vienna. 



Fio. 959. 



A, Risfioa turbinata (Laiii.). 

 Oligocene; Weinheim, near 

 Alzey. B, R. (Alvania) mon- 

 tagui Payr, Miocene ; Steina- 

 brunn, near Vienna. 



Family 12. Turritellidae 

 Gray. 



Shell turreted, with high 

 acuminate spire. TFhorls numerous, iisually spirally rihhed or striated. Aperture oval, 

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

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



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

 quadrilateral ; outer lip thin, excavated behind, and 

 slightly produced in front. Trias to Recent ; maximum 

 in Tertiary. The older Mesozoic species are usually 

 small. 



961). Like the last, 



Subgenera : Mesalia Gray (Fig, 

 but aperture with shallow canal, 

 Tertiary to Recent. 



Protoyna 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. 



Glauconia Gie- 

 bel (Omphalia 



Zekeli ; Gassiope 



Coq.) (Fig. 962). 



Thick-shelled, coni- 



cal or turreted, 



narrowly umbili- 



cate. Whorls 



spirally ribbed, rarely smooth. Aperture oval, with faint canal 

 anterior and median emargination. Abundant in the Cretaceous. 



and twisted inner lip. 



Fig. 960. 



A, Turritella turris Bast. (T. 

 ir<'e?(raZiet. nonLinn.). Miocene 

 Moljisse ; Eriningen, near Ulm. 

 B, T. imhricataria Lam. Cal- 

 caire Grossier ; Grignon, near 

 Paris. 



Turritella (Mesalia) 

 multisulcata Lam. 

 Eocene ; Calcaire 

 Grossier ; Grignon, 

 near Paris. 



Fig. 962. 



Glauconia kefersteini 

 Goldf. Middle Cre- 

 taceous ; Dreistätten, 

 near Wiener-Neust. 



outer lip with 



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



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

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

 Recent. 



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

 them nevertheless in the structure of the shell and spiral protoconcli. The determina- 

 tion of the few Paleozoic and Mesozoic forms is uncertain. 



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

 irregularly tubulär, internally vitreous, and often with septa. Carl)oniferous (?) to 

 Recent. Abundant in the Tertiary. 



