Subfamilies, Genera, and Subgenera — Recent and Fossil 97 



1855. SegmcHti)ia Moquin-Tandon, Hist. Moll. Terr. Fluv. France, II, pp. 423, 424. 



Typo Planorbis nitidus Miiller. As genus 

 1865. Scgmentina Binney, L. and F-W. Shells N. A., II, p. 136. No type cited. As 



genus 

 1867. Appendicular id (])art) Ficinus, Zeits. fiir gesamm. Naturw., XXX, p. 363 

 1870. Segmcntina D.'VLL, Ann. N. Y. Lye. N. H., IX, p. 352. Type Planorbis lacustris 



Lightfoot. As genus 



1883. Segmenlina Fi.scher, Man. de Conch., p. 509. T.ype Planorbis nitidus Mi'ill. As 



subgenus of Planorbis 



1884. Segmentina Tryon, S. and S. Conch., Ill, p. 107. Type Segmentina lacustris 



Lightfoot. As genus 



1885. Segmentina We.steklund, Fauna Pal. Reg., V, p. 85. Xo type cited. As sub- 



genus of Planorbis 



1886. Segmentina Glessin, Syst. Conch. Cab., ed. 2, XVII, p. 34. Tj'pe Planorbis 



nitidus Miiller. As genus 

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



nitidus Miiller. As subgenus of Planorbis 

 1905. Segmentina Dall, Alaska Moll., p. 97. Type Planorbis nitidus Miiller. As genus 

 1912. Segmentina Hannibal, Proc. Mai. Soc. Lond., X, p. 154. Type Planorbis nitidus 



Miilleir. As subgenus of Planorbis 

 1915. Segmentina Preston, Fauna Brit. India, Moll. FW. Cast, and Pelec, p. 124. 



Type Phnwrbis nitidus Miiller. Includes species now referred to Helicorbis, 



Trochorbis, and Polypylis 



1917. Segmentina L. Soos, Ann. Hist. Nat. Musei Hungarici, XV, pp. 140, 142. Type 



Planorbis nitida Miiller. As genus 



1918. Segmentina Walker, Miscel. Pub., Mus. Zool., Univ. Mich., Xo. 6, p. 13. Type 



Nautilus lacustris Lightfoot. As genus 



1919. Segmentina Annand.ale and Prash.\d, Rec. Ind. Mus., XVIII, p. 56. Type 



Planorbis nitidus Miiller. As genus 

 1921. Segmentina Germain, Rec. Ind. Mus., XXI, p. 163. T.ype Planorbis nitidus 



Miiller. As genus 

 1923. Segmentina Wenz, Fossil. Cat., pars 22, p. 1661. Genotype Segmentina lacustris 



(Mantagu). As genus 

 1926. Segmentina Lindholm, Archiv. fiir Mollusk., 58 year. Heft 6, p. 252. Monogeno- 



type Nautilus lacustris Lightfoot {^Planorbis iiitidus Miiller). As genus 



1926. Segmentina Kennard and Woodward, Syst. Brit. Non-Marine Moll., p. 89. Tj^pe 



Planorbis nitidus Miiller. As genus 



1927. Segmentina Pilsbry and Beqluert, Bull. Amer. Mus. N. H., LIII, p. 128. Type 



Planorbis nitidus Miiller. As genus 



1929. Segmentina H.aas, Trab. Museo Cien. Nat. Barcelona, XIII, p. 388. Type evi- 

 dently Planorbis nitidus Miiller. As genus 



1931. Segmentir^a Germain, Moll. Terr. Fluv. France, II, p. 542. Type Segmentina 

 nitida (Miiller). As genus 



1931. Segmentina Thiele, Handbuch, Teil 2, \). 481. Type Anisus (S.) nitidus (Miiller). 

 As subgenus of Ajiisus 



1935. Segmentina A. Soos, Allat. Kozlem., XXXII, p. 29. As genus 



Shell (plate 79, figs. 1-3). Small, ultradextral, smooth, and glossy; 

 whorls few, notably overlapping the body whorl embracing most of the 

 preceding whorls, causing the preceding whorl to project far within the 

 width of the aperture; periphery rounded or carinated. Cavity of the last 

 whorl restricted by several barriers, each set usually composed of three 

 large transverse lamellae, parietal, basal, and palatal. There may be other 

 smaller lamellae (plate 76, fig. 4). The internal lamellae are composed of 

 enamel-like substance. The embryonic whorls have spiral rows of small pits. 



