64 The MoUuscan Family Planorhidae 



The intestine crosses over the oesophagus and extends toward the forward 

 part of the body, but there is no bending backward with a posterior loop 

 as in the Helisoniatinae. As in Anisus, there is no sharp division into crop, 

 gizzard, and pyloris. The pyloric portion of the stomach appears to merge 

 with the intestine. Germain states that it is absent. The buccal sac is as 

 in Anisus. 



The jaw is like that of Planorbis planorbis, the superior portion having 

 about twentv plates. 



The radula (plate 68, fig. 1) formula is 15-1-15 with 140-145 rows of 

 teeth. Central tooth bicuspid, nearly reaches to the lower margin of the 

 base of attachment. Lateral teeth (1-8) are tricuspid with a small addi- 

 tional cusp above the ectocone, placed high up on the reflection. The inter- 

 mediate teeth (9-11) differ by having the reflection placed higher on the 

 tooth, with four cusps, the ectocone split into three cusps. Marginals (12- 

 15) with five cusps are like the intermediate teeth, the reflection very high 

 on the tooth. The outer marginal (15) is very narrow. 



For the anatomical data herein presented, four specimens were dis- 

 sected, collected by A. Jankowski, at Drewnica, a turfy ground 4 km. 

 northeast of Warsaw, Poland. 



Geographical Distribution. This group extends throughout Europe 

 from the British Isles and Portugal eastward to Russia and Siberia, as 

 far east as Kamchatka (Eyerdam, 1928). Southward the distribution in- 

 cludes the countries bordering the Mediterranean Sea and the Caspian Sea. 



Species Considered as Valid. Ajiparently but two species are included 

 in this group: Anisus ( Bathyoniphalus) contortus (Linn.) of Europe and 

 Asia, and Anisus (Bathyoniphalus) dispar (Westr.) of Sweden and Russia. 



Geological Distribution. From the Miocene period to the Recent 

 period. 



Remarks. In anatomical features Bathyoniphalus so nearly resembles 

 Anisus that there seems little reason for recognizing the group as distinct. 

 The genitalia strongly resemble those of Anisus septemgyratus. The in- 

 ternal structure of the penial complex is similar. The kidney shows some 

 differences in cross section (compare plate 46, fig. 20, with plate 47, figs. 

 14-16). However, the shell is distinctive and the name has been in use 

 for so long a period that it should be retained as a subgenus of the old 

 group Spiralina { = Anisus). It should be noted that the radula formula is 

 the same as in Anisus and different from that of Planorbis. 



Genus ODONTOGYRORBIS Lorenthey, 1906 

 Type by original designation Planorbis krambergeri Halavats 



1906. Odontogyrorbis Lorexthey, Beitrage zur Fauna unci stiatigraphischen Lage der 



pannonischen Schichten in der Umgebung des Balaton-Sees. Resultate d. 



wissenschaftl. Erforschung des Balatonsees, I, 1, Art. 3, p. 121. Genotype 



Planorbis krambergeri Halavats. 

 1923. Odontogyrorbis Wenz, Fossil. Cat., Pars. 22, p. 1538. Genotype Paraspira 



(Odontogyrorbis) krambergeri Halavats. As subgenus of Paraspira. 



Shell (plate 76, figs. 1, 2). Very small, discoidal, flattened, whorls rela- 

 tively few, closely coiled, increasing very slowly in diameter, each side 

 showing all of the volutions, right side slightly concave, left side almost 

 flat; the aperture contains three lamellae, one on the base of the lip and 



