SEGMENTINA. uy 
C. M{NIMUM (smallest) Miiller. Pl. V., f. 9. 
Sub-fusiform, semi-transparent, white, rather solid, glossy, micro- 
scopically striate in the line of growth; whorls 553; spire pointed ; 
mouth ovate, with 3 denticles. A.1?mm. B. ~ mm. 
There is no mistaking this little shell when once seen. 
It must be examined under a lens to be fully appreciated. 
It is worth while to wait for the animal to come out, and 
travel over a moist decayed leaf, when the conspicuous 
black spots that constitute its eyes can be seen and their 
sessile position noted; indeed, these eyes may be seen 
through the shell, so dark are they and so transparent 
the shell. 
It is very common under stones, logs, etc., in moist 
shady situations throughout the whole of the British Isles. 
Var. ¢rident.ita (Risso). Denticles slightly more 
distinct. 
Family. —LIMN#IDA. 
Subfamily, —PLANORBINE. 
Genus.—SEGMENTINA Fleming. 
Shell coiled, *dextral with internal transverse septa. 
So NIvipA (sheniug) Miller... Pl. Vi, & 2. 
[=P.. LINEATUS, Wadker]. 
Quoit-shaped, compressed, more convex above than below, semi- 
transparent, pale rufous horn-colour ; cavzvated; whorls 4; spire sunk ; 
wnibelicus narrow but deep. Its special characteristic is the nautilus- 
like septa which are visible from the outside of the shell at intervals 
across the whorls. A. 13mm. B. 5mm. 
*There is much doubt whether the shells of this genus are dextral or sinistral ; 
pending the decision of the anatomists I have retained the old nection. 
