100 The Molluscan Family Planorhidae 



kempi Preston and angusta Jickeli, may be true Segmentina. Species 

 quoted from northern Africa probably belong to other genera, as Ajropla- 

 norbis. South African species may belong to an undescribed group. The 

 Indian and Chinese species included by authors in Segmentina probably 

 all belong to Poli/pylis, Pingiella, or Helicorbis. Only an anatomical ex- 

 amination can correctly place the many species referred to segmentina. 



Geological Distribution. Oligocene period to Recent fauna. 



Species Considered as Valid. Since the genus Segmentina is not found 

 in America, it is extralimital to the scope of the present work. Segmentina 

 7}iti(Ja (Miillerl, the genotype, is the only species definitely considered. 



Remarks, The genus Segmentina is distinguished not only by its glossy 

 shell with the embracing body whorl and internal barriers, but also by its 

 genitalia with the two short flagella on the verge, the few large ovotestis 

 diverticula, the ductless penial gland in the preputium, and the papilla at 

 the end of the verge. No mention is made of this peculiar gland in any 

 w^ork consulted. The prostate is on a separate duct as in the Planorbinae. 

 These special features of the anatomy distinguish Segmentina from all 

 other genera of Planorbidae. 



The generic name has been used in a rather wide sense and has included 

 one group which belongs in another subfamily {Planorbula) and several 

 other related groups which are separated generically from Segmentina 

 {Popypylis, Pingiella, Helicorbis) . As typified by Planorbis nitidus Miiller 

 it is a well characterized genus. 



Segmentina nitida appears to be a favorite host for parasitic worms, 

 all of the twelve specimens examined being more or less heavily infested. 

 The ovotestis appeared to be most affected and in several specimens this 

 organ was almost obliterated. The liver was also affected. 



Genus HIPPEUTIS (Agassiz AISl Charpentier, 1837 



Type designated by Clessin in 1886, Pknwrbis complanatus Drap. {= Helix 

 jontana Lightfoot), one of the two species originally included 



1837. Hippeutis 'Aga.ssiz' in J. de Ch.^rpentier. Neue Denksch. Allg. Schweiz. Naturw., 

 I, No. 2, p. 22. As subgenus of Planorbis 



1837. Hippeutis Gr.\y, in Turton, Man. Land FW. Shells Brit. IsL, Ed. 2, p. 243. As 

 subgenus of Planorbis 



1844. Hippeutis Hartm.\nn, Erd-und Siisswussser-Gast. der Schweiz., V, pp. 51, 87. 

 As subgenus of Planorbis 



1850. Hippcutes M. E. Gr.\y, Fig. Moll. Anim., IV, S^vst. Arrang., p. 119. Typographi- 

 cal error for Hippeutis 



1850. Segmentina (part) Stein, Leben. Schneck. Muschl. Berlins, p. 78. Xon Seg- 

 mentina Fleming, 1817. (Segmentina plus Hippeutis) 



1855. Hippeutis Moquin-T.4Ndon, Hist. Moll., Terr. Fluv. France, II, pp. 423, 426. 

 Type Planorbis jontanus (Lightfoot). As genus 



1885. Hippeutis Westerlund, Fauna Palearc. Reg. Binnen. Conch., V, pp. 65, 84. No 



type cited. As subgenus of Planorbis 



1886. Hippeutis Clessin, Syst. Conch. Cab., Ed. 2, XVII, p. 34. Type Planorbis com- 



planatus Drap. As subgenus of Planorbis 



1902. Hippeutis Westerlund, Rad. Jugoslav. Akad., 151, p. 121. Type Planorbis 

 jontanus (Lightfoot). As subgenus of Planorbis 



1905. Hippeutis D.\ll, Alaska Moll., pp. 82, 86. Type Planorbis fontanus (Lightfoot). 

 As subgenus of Pla^wrbis 



1912. Hippeutis H.-vnnib.al, Proc. Mai. Soc. London, X, p. 154. Type Planorbis com- 

 planatus Drap. (= Helix jontana Lightfoot). As subgenus of Planorbis 



I 



