AND ALLir.l) FORMS. 53 



The following species may be added : — 



A. decisa, Hald., loc. cit., p. 7, pi. i, fig. 2, 3. Pennsylvania. 

 A. pallida, Hald., loc. cit., p. 12, pi. i, fig, 7. Lake Chainplain. 

 A. p^rata, Hald., loc. cit., p. 13, pi. i, fig. 8. Northern United States 

 and Canada. 



See also on p. IG, ante, foi* others. 



I.ITHOGI.YFHUS, Muhlfeldt. 



Lithoglyphus, Muhlfeldt, in Hartmaun's Moll, of Sturm's " Fanua 



Deutschlauds," VI, (1821) p. 57. 

 Lithoglypter, Fitz., Syst. Verz., (1833) p. 116. 

 Lithoclypus, Villa, Disp. Syst., (1841) p. 36 (fide Hermannseu). 



Shell globular, thick, smooth, imperforate ; spire short ; suture 

 not impressed. Aperture broadly sul)0vate, or nearly circular, 

 nearly as broad as long ; inner lip callous ; outer lip simple. 

 Operculum corneous, rounded. 



Soft parts of L. lapidum : Foot large, longer than the shell. 

 Tentacles short, rather tapering and pointed. Verge bifid from 

 the base, forks cylindrical, the posterior being two-thirds as long 

 as the anterior one. 



Lingual dentition of L. fuscus, according to Troschel :^ Rha- 

 cuidian tooth less than twice as broad as long. Body of inter- 

 mediate tooth longer than broad ; peduncle rather short. Outer 

 lateral tooth with fewer denticles than the inner. Formula of the 

 <ienticles : g^^ - 7 - 8 - 6. 



The only notice we have of the eggs is the following by D'Or- 

 bigny with regard to L. joeristomatuti'^ :-w-" They live in numerous 

 families ; each shell carries oval eggs which are afiSxed to it." 

 "We cannot determine from this notice whether the eggs are de- 

 posited singly, or in groups covered by a common ova-capsule. 

 Probably the latter arrangement is meant. 



Station, fresh water. 



Distribution, Southeastern Europe and South Americn. 



Type L. naticoides, H. & A. Adams, Gen. Rec. Moll., I, (1854) 321, pi. 

 xxxiv, fig. 1, fl, b, c. — Pahidina naticoides, Ferrusac, Ki^stek, Monog. 

 Paludin., p. 47, pi. ix, fig. 23-26. Bab. Moldavia, Dalmatia, etc. 



The following species are apparently congeneric : — 



L. fuscus, Zgl. — Pahidina fusca, KiiST., Monog. Paludin., p. 46, pi. ix, 

 fig. 19-22. Southern Russia. 



' G-ebiss der Schnecken, I, 105, pi. vii, fig. 12. 

 2 Voy. Am. Merid., Moll., p. 382. 



