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SYNOPSIS OF THE GENERA OF ENDODONTIDA. 
Group POLYPLACOGNATHA. 
Jaw composed of numerous squarish plates connected by mem- 
brane only ; side teeth all bicuspid ; no mucus gland at tail. 
Shell subtrochiform, keeled, at least in young, usually flame- 
painted. Laoma. | 
Aperture of shell without teeth or folds. 
Section PHRIXGNATHUS. 
Group HaPpLocona. 
Jaw composed of overlapping lamin, partially soldered together 
or solid, and vertically striated. 
Tail with a mucus gland ; aperture without folds. 
[FLAMMULINA. | 
Jaw arcuate, with flat plaits. 
Central tooth a short mesocone, ectocones obsolete, laterals 
with a short ectocone, which disappears on the mar- 
ginals, leaving a long oblique mesocone only. 
s.g. THALASSOHELIX. 
Marginal teeth low, wide, and multicuspid. 
s.g- HEDLEYCONCHA. 
No mucus gland at tail. 
Aperture armed within with teeth or plates. 
[Expoponra. | 
Shell rounded at periphery, outer lip with folds. 
Section THAUMATODON. 
Aperture without teeth; shell depressed, convex, flat, or 
concave. s.g. CHAROPA. 
SYNOPSIS OF THE GENERA OF HELICIDA. 
Sus-FAMILY MacrooGona. 
Genitalia without flagellum. Eggs or embryonic shell large. 
Vagina or spermatheca duct bearing a blind sack ; lip of shell 
narrow or simple. 
Shell discoidal. PEDINOGYRA. 
Shell subtrochiform. ANOGLYPTA. 
Shell bulimoid. 
Upper whorls spirally lirate, with crenulated suture. 
CARYODES. 
Upper whorls finely beaded or smoothish, suture even. 
PANDA. 
SuB-FAMILY EPIPHALLOGONA. 
Genital system having an epiphallus and flagellum on penis, 
and no dart-sack and associated mucus gland. 
