44 
*** Gills plumose, exposed, lamine pinnate, spirally twisted. 
Fam. 39. Vanvatip#. Operculum orbicular, spiral, many- 
whorled (fig. 24). Valvata. 
in 
Fig. 24.— Valvata piseinalis. 
b. Eyes sessile, on the head between or rather behind the base of 
the tentacles. 
Fam. 40. Cacip. Shell subcylindrical, arched ; apex deciduous, 
subspiral ; operculum circular, horny ; foot short; teeth 3-1-3; 
jaws distinct. Caecum. 
Fam. 41. TruncaTetuip#. Body and shell spiral; foot very 
short, roundish; muzzle broadly 2-lobed; walks with its foot and 
lps; teeth 3-1°3; gill ?; operculum horny, spiral. Trunea- 
tella. 
Fam. 42. Actcutap&. Body and shell spiral; foot short, di- 
vided ; gills ——?; operculum horny, spiral. Acicula, Geomelania. 
G. Operculum none ; mantle and shell simple in front ; gills in an 
oblique line across the mantle-cavity ; lamine elongate, linear, partly 
exposed ; eyes small, on the outer side of the base of the tentacles. 
Fam. 43. Caputip™. Foot folded on itself (fig. 25). Capulus, 
Hipponyx, Amalthia, Amathina. 
Fig. 25.—Capulus hungaricus. 
Fam. 44. Catyprraipm. Foot expanded (fig. 26). Crypta, 
Galerus, Crucibulum, Calyptrea, Trochita. 
Fig. 26.—Calyptrea sinensis. 
