—- 1 — 
Planorbis infraliratus' nov. sp. 
Testa discolor, supra rufescenti-cornea, infra albida, firma’ 
solida, nitida, supra in centro immersa, subtus latius 
umbilicata, supra sublaevigata vel sub lente creberrime 
striatula, infra striis densissimis transversis ornata, liris 
obsoletis vel lineis elevatis 4 parallelis spiralibus mu- 
nita; anfr. 4, celeriter accrescentes, sutura sat pro- 
funda disjuncti, ultimus latus, supra convexus, pone 
suturam obtuse angulatus, peripheria rotundatus, infra 
planiusculus; apertura perobliqua, lunato-ovata, peri- 
stomate simplici, acuto, marginibus longe distantibus, 
callo tenui albo junctis, exteriore longe provecto. Diam. 
maj. 41/,, min. 3%),, alt. 1!/), mm. 
Hab. in Sibiria prope Jenissei ad Nischnij Inbaltsk (lat. 
63° 50°). 
Valvata sibirica Midd. restit. Westerl. 
Testa discoidea, supra omnino plana, subtus late umbili- 
cata, virescenti-cornea, transversim dense sublamellato- 
striata, argenteo-micans; anfr. 3!/,, forte accrescentes, 
cylindracei, ultimus ınagnus, aperturam versus dila- 
tatus et ampliatus; apertura magna, circularis, peristo- 
mate undique recto, continuo, margine superiore quam 
anfr. penult. humiliore. Diam. maj. 5, min. 3?],, apert. 
2 mm. longa et lata. 
Valv. erist. Müll. var. sibirica Midd. ass). & V. cristata 
Midd., Gerstf. & Schrenk. 
— var. frigida Westerl. 1873: testa transversim striata, 
vix nitidula, obseura. | 
Hab. in Sibiria prope Jenissei ad Lusino (lat. 68° 35), 
 "Surgutskoj (lat. 62° 50%) et Worogowa Selo (lat 60° 
50‘) saepius frequens. Var. ad Worogowa Selo. Testi- 
bus clariss. Middendorff, Gerstfeldt et Schrenk haee 
species ubique in Sibiria tota et’ ad Amur occurrit. 
