CLASR IV 



GASTROPODA 



545 



Staliola Brusina. Outer lip thickened ; operculum calcareous. Cretaceoiis to 



Miocene. 

 .1 (' Fosmrulus Neuinayr. Like tlie last, but vvitli Bpiral ribs. 



Upper Miocene. 

 HWL z*^ Nematura Benson {Stenothyra Benson) (Fig. 953). Like 



Bithinia^ but aperture contracted. Operculum calcareous, spiral. 



Tertiary and Recent. 



Fig. 952. 



A , Bithinia tentaculata 

 (Linn.). Upper Mionene; 

 Miocic, Dalmatia. B, 

 Operculum of same. C, 

 B. gracilis Sandb. Fresh- 

 water Molasse ; Ober- 

 kirchberg, near Ulm. 



Fio. 953. 



Nematura ptipa (Nyst). 

 Oligocene ; Hackenheim, 

 near Alzey. 



Fio. 954. 



Nystia chastelii 

 (Nyst). Middle Oligo- 

 cene ; Klein-Spouwen, 

 Belgium. 



Fm. 955. 



Hydrohia acuta A. 

 Braun. Miocene ; 

 Weissenau, near 

 Mayence. 



Nystia Tourn. {Forbesia Nyst) (Fig. 954). Outer lip reflected ; operculum 

 calcareous, spiral. Tertiary and Recent. 



Assiminea Leach. Tertiary and Recent. 



Hydrohia Hartm. {Littorinella Braun ; ToiLrnoueria Brusina) (Fig. 955). Conical 

 to turreted, acuminate, smootli, Aperture oval ; operculum homy, paucisj)iral. 

 Cretaceous to Recent. The Indusia Limestone (Lower Miocene) of Auvergne is 

 almost exclusively composed of the shells of H. duhuissoni Bouill. Similarly, the 

 Littorinella Limestone of tlie Mayence Basin, wliich is of equivalent age, is made 

 up of the Shells of H. acuta Braun. Strata in the fresh-water limestone of Nördlingen 

 are charged with H. trochulus Sandb. ; and the Upper Eocene marl of St. Ouen is 

 filled with the remains of H. fusilla (Prev.). 



Other genera and subgenera closely related to the foregoing are Bythinella Moq. ; 

 Amnicola Gould ; Belgrandia and ^ ^ ^ 



Lartetia Bourguignat ; Lappare^itia 

 Berthelin. 



Pyrgula Christofori and Jan. 

 (Fig. 956, Ä). Turreted, whorls 

 spirally keeled or ribbed. Peristome 

 continuous. Tertiary and Recent. 



Genera allied to the last are 



Micromelania Brus. (Fig. 956, 5) : , „ 



. rx 1 /-r-. r, Jy. ^» Py^gula eugeiiiae Neumayr. 



Mohrensternia ötol. (Fig. 956, C); Upper Miocene; Arpatak, Transyl- 



Pyrgidium Tournouer ; Prososthenia SSi (N»ima"r' Uppi? mS"! 



Neumayr. Tertiary. Miocic, Dalmatia. C, Mohrensternia 



T -±1 1 i, ry- 1 /■x^• nc^7\ m^«ta Andfzewsky. Congerien Stage 



Llthoghjphus Ziegl. (Fig. 957). (Miocene) ; Inzensdorf, near Vienna. 



Globose or ovate, with short spire ; 



rather thick and aolid. Aperture large, obliquely oval ; inner lip thickened. 

 Tertiary and Recent ; Europe. Similar forms, Somatogyrus Gill, and Flumincola 

 Stimpson, occur in North America. There are other related genera in south-eastern 

 Asia and South America. 



Fio. 956. 



Fio. 957. 



Lithoglyphus fusciis 

 Ziegler. Upper Mio- 

 cene ; Malino, West 

 Slavonia. 



Family 11. Rissoidae Troschel. 



Shell small, thick, turhinate to turreted, usually ribbed or spirally striated, rarely 

 smooth. Aperture oval, angular posteriorly, often with anterior canal. Operculum 

 homy, paucispiral. Jura to Recent. 



Eissoina d'Orb. (Fig. 958). 

 VOL. I 



Turreted, transversely ribbed, rarely smooth : outer 



2 N 



