Subfamilies, Genera, and Subgenera — Recent and Fossil 101 



1915. Hippcutiii Prestox, Fauna Brit. India, Moll., FW. Gast and Pelec, p. 124. Type 

 Planorbis jontanus (Lightfoot). As section of Phuiorbia 



1918. Hippeutis Walker, Mis. Pub. Zool. Mus., Univ. Mich., No. 6, p. 94. Type Pla- 

 norbis jontanus (Lightfoot). As subgenus of Planorbis 



1923. Hippeutis Wexz, Fossil. Cat., Pars 22, p. 1633. Genotype Hippeutis compla- 

 natus (Drap.) = Helix jontana Lightfoot. As genus 



1923. Hippeutis Germ.ain, Rec. Ind. Mus., XXI, pp. 8, 159. Type Planorbis jontanus 

 (Lightfoot). As subgenus of Planorbis 



1926. Hippeutis Lixdholm, Archiv. fiir Mollusk., 58 year, Heft 6, p. 253. Ideogeno- 

 type Planorbis complanatus Drap. As genus 



1926. Hippeutis Kenxard and Woodward, Syn. Brit. Non-Marine Moll., p. 69. Type 



Helix complanatus Linn. As subgenus of Planorbis 



1927. Hippeutis Pilsbry and Bequaert, Bull. Amer. Mus. N. H., LIII, p. 128. Type 



Planorbis complanatus Drap. = P/«nor6zs jontanus (Lightfoot). As subgenus 



of Planorbis 

 1929. Hippeutis ^as, Trab. Museo Cien. Nat. Barcelona, XIII, p. 387. Type evidently 



Helix jontana Lightfoot. As genus 

 1931. Hippeutis Germaix, Moll. Terr. Fluv. France, II, p. 541. Type not cited but 



Planorbis complanatus (Linn.) described. As subgenus of Planorbis 

 1931. Hippeutis Thiele, Handbuch, Teil 2, p. 481. Type Anisus (H.) complanatus 



(Linn.). As subgenus under genus Anisus 

 1935. Hippeutis A. Soos, Allat. Kozlem., XXXII, p. 29. As subgenus of Segmentina. 



No tj-pe cited 



Shell (plate 79, figs. 4-6). Small, ultradextral, lens-shaped, shining, the 

 body whorl very wide and overlapping most of the inner whorls and form- 

 ing a sharp keel at the periphery, the preceding whorl forming a sharp 

 extended ridge on the parietal side of the aperture. Aperture triangular, 

 outer lip thin. There are no barriers or lamellae within the aperture. The 

 embryonic whorls have spiral punctures as in Segmentina. 



Animal. Not differing from that of Segmentina in general form. The 

 body of the animal is clear and translucent. 



ANATOMICAL CHARACTERISTICS 

 PLATE 2 {Hippeutis complanatus (Linn.) ) 



GENITALIA. Male Organs (fig. 15) . Seminal vesicle rather short 

 (about 0.7 nun.), placed midway between ovotestis and oviduct, the di- 

 ameter of the organ about the same as the ovosperm duct, with many 

 pustule-like vesicles. Prostate short (about 0.6 mm.) with ten long and 

 narrow diverticula. Free portion of prostate duct short (fig. 8). Sperm duct 

 iSPD) long (over 1 mm.) and of large diameter. Vas deferens (VD) about 

 as long as sperm duct, but of smaller diameter. 



Penial complex (plate 2, fig. 14) less than 1 mm. long. Preputium (PR) 

 strikingly pyriform, tapering to a narrow neck near the outlet. Vergic sac 

 (VS) shorter than the preputium, sac-like, of much smaller diameter than 

 the preputium. There are two short flagella (FL). There is a single wide 

 retractor muscle (RM) attached to the preputium at the lower part of the 

 bulbous swelling. 



Internally (fig. 12), the preputium has two large fleshy pilasters (PL), 

 to the left one of which is attached a large, sac-like penial gland, which 

 extends crosswise of the preputial cavity (SB). There is a depression at the 

 end of the gland but apparently no cavity or cup. The square end of the 

 gland is folded backward upon itself. It is shown folded in fig. 12 (SB) and 

 with the end stretched out in fig. 9, where the small depression may be 



