124 LIMNiEIUiE. 



250. Planorbis (Gyraiilus) issykulensis, Clessin. 



Planorhis ( (Ji/raitlus) issykulensis, Clessin, Nacbr. 131. Malak. Ges. 

 xxxix, 1907, p. 7. 



iShell small, slightly compressed, wiiorls 4, rapidly increasing 

 (the last scarcely one-third of the total diameter of the shell) ; 

 suture moderately deep ; umbilicLis rather wide; sculpture fine, 

 irregular ; aperture oblique, compressedly ovate. 



Alt. 1-:^, diam. 4'5 mm. 



Hah. Pamirs, from only one locality, but very plfutiful. 



Section HIFPECTE^. 

 Hippeutes, Agassiz, Nouv. Mein. Soc. Ilelv. i, 1S37. 

 Type, Planorhis fontanus, Lightfoot ; Europe. 



Uanrje. Europe; Asia. 



Sliell small, lenticular, much depressed, paucispiral ; whorls very 

 rapidly increasing, carinate ; aperture obliquely heart-sliaped. 



251. Planorbis (Hippeutes) versicolor, Westerhmd. 



Planorhis {Hippeutes) versicolor, Westerhmd, in Vega Exped. 

 Vetenskapliga Jakttagelser, iv, p. 20(3, pi. 4, tig. 19. 



Original description: — Testa juvenis riii'o-castanea, nitidissima, 

 adulta rufescenti-cornea, nitidula, subtilissime oblique striatula, 

 supra convexa, centro sat profunde immersa, subtus plauiuscula, 

 umbilicata (uuibilico centro augustissimo, aperturam versus 

 dilatato) striatula ; anfr. 4, primi angusti, spiram minimam for- 

 mantes, ultimus maximus, extus declivis, subtus convexiusculus, 

 peripheria acute angulatus ; apert. perobliqua, cordiformis, 

 margine columellari subrecto, exteriore antrorsum valde convexo. 



Alt. 1"5, diam. 5 mm. 



Hab. Point de Galle, Cevlon. 



Subgenus SEGMENTINA. 

 Segmentina, Fleming, Hist. Brit. Anim. 1828, p. 279. 



Type, Planorhis nitidus, Miiller ; Europe. 



Range. Europe ; A sia ; Africa ; Australia. 



Shell orbicular, depressed, furnished internally witli transverse, 

 testaceous partitions or teeth ; aperture transversely oval, or 

 circular. 



See also description of Planorhis, p. 115. 



