VERTIGO. 97 
Genus. —VERTIGO ALiller. 
Animal with only two tentacles ; sZe// subcylindrical or fusiform, 
dextral or sinistral; most species with denticles; zdz/écus minute. 
In order to aid the collector to identify these minute 
shells I have tabulated some of the characteristic distinc- 
tions of those which are dextral and denticulate.* 
The species have been conveniently arranged as follows: 
A.-—DEXTRAL, DENTICULATED, V, antivertigo, V. moulin- 
stana, V. pygmea. V. alpestris, V. substriata. 
B.—SinistraL. V. pusilla, V. angustior. 
C.—DEXTRAL, WITHOUT TEETH. VJ. edentula, V. minu- 
tisstma. 
A. DEXTRAL, denticulated. 
Sub-genus.— ALa@a Seifreys. 
I. V. ANTIVERTIGO (vot reversed) Draparnaud. PI. IV.,f. 14. 
Oval, tumid, thin, semi-transparent, glossy, rufous horn-colour: 
whorls 4%, tumid; sfzve short, abrupt ; outh semi-oval, contracted in 
the middle of the outer edge; zeeth 6—9 of a reddish brown colour ; 
umobelicus distinct. A. 13mm. B. t mm. 
Found in moist places under logs, stones, among moss, 
and on water plants by the water side. It is recorded for 
nearly all the English counties and for several in Scot- 
land, but only locally, as yet, for Ireland and Wales. 
Young specimens have only two denticles, one on the 
pillar and one at the base of the penultimate whorl. 
Var. I. dctodentéta ( Stud. ). With 8 denticles. 
Var. II. séxdentéta (Mont. ). With 6 denticles. 
* See page 103. 
