HELICIGONA. 299 



flat, two-edged head (fig. 21) ; spermatheca duct branching into a 

 diverticuluin about as iorig as itself. 



This section contains a single species commonly distributed 

 throughout middle and northern Europe. 



H. lapicida L. iv, 117. 



v. medalpedensis Cl. iv, 261. 

 v. andorrica Bgt. 



Section Chilostoma Fitziuger, 1833. 



Chilostoma FITZ., Syst. Verz., 1833, for C. corneum (=H. cornea 

 Drap.), C. zonatum (=foetens Stud.) C. pulchellum (=pulchella 

 Miill., type of the prior genus Vallonia). CHARP., Cat. Moll. Terr, 

 et Fluv. Suisse, 1837, p. 8, for cingulata, zonata, fastens, pulchella. 

 GRAY, A List of the Genera of Recent Mollusca, their Synonyma 

 and Types, P. Z. S. 1847, p. 172 (type H.fcetens).M.oqv IN-TAN- 

 DON, Hist. Nat. Moll. Terr, et Fluv. France, ii, p. 131, for fcetens 

 and cornea. Campylcea BECK, Index Moll. 1837, p. 24. LOWE, P. 

 Z. S. 1854. ALBERS, Die Hel. 1850, p. 81. MARTENS, Die Hel. 

 1860, p. 122 (type H. cingulata Stud.). Cingulifera Held, Isis, 

 1837, p. 911, for ziegleri Schm., intermedia Fer., cingulata Stud., ar- 

 bustorum L., etc. Corneola HELD, ibid., p. 912, for hirta, feburiana r 

 setipila, planotspira. fattens, pulchella, etc., etc. Zoniies HARTM., 

 Gastr. Schw., p. 161, not of Montf. Eucampylcea PFR., Noinencl. 

 Hel. Viv. 1878, p. 144. WESTERLUND, Fauna, p. 103. 



Shell depressed, openly umbilicated, with convex spire and 

 rounded (rarely keeled) periphery. Surface unicoloied or 1-3 

 banded, smooth, costulate or hirsute. Whorls about 5?, the last 

 deflexed in front ; aperture wide lunate or suboval, toothless or with 

 a basal tooth; peristome narrowly expanded, reflexed below, dilated 

 at columellar insertion, rarely continuous across the parietal wall. 

 Type H. foetens Studer. (See pi. 43, figs. 27, 28, H. planospira 

 Lam. ; pi. 43, fig. 42, H. setosa Ziegler.) 



Jaw strong, with 2 to 10 stout ribs grouped near the middle. 

 Radula with mesocones only developed on median and lateral teeth ; 

 marginals with an inclined bifid inner and small outer cusp. Geni- 

 talia as described for the genus. 



In the recent fauna this group is characteristic of the Alpine 

 Mountain system, extending down the Italian peninsula to Sicily, 

 and the Balkan peninsula to southern Greece.' A few species occur 



