t^^l

128 ARCIBJE.
Hulla, Linnseus, etc.
Planorbis, Miiller.
2'urbo, Costa.
Bulimus, Bruguiere, I'oiret.
Limnea, Sowerby.
TiPB, PJiysa fontinalis, Linn.; Europe.
Range. Europe ; Asia; Africa ; America.
Shell fluviatile, horny, thin, spiral, sinistral, generally ovate
acuminated ; outer lip sharp, simple ; inner lip expanded, continuous
with the columella ; columella tortuous, single-plaited.
260. Physa coromandelica, Dunher.
Phym coromandelica, Dunker, jVTalak. Blatt. 1862, p. 150.
Original description:—Testa subovata tenuis, fusco-cornea, subdiapliana,
anfractibus quinis earinatis, per longitudinam striatis,
sutura distincta divisis instructa ; spira parum exserta, ob carinam
prorainentem scalata; anfractus embryonalis vel apes obtusiusculus
; apertura ovato-oblouga obhqua ; spira duplo major; labrum
aeatam m mzTgme sapeviore asguhtum,
Alt. 11, diam. 5'6 mm.
Hah. Ooromandel. i
Class PELECYPODA.
Order TETE A BR AN C H I A.
Suborder MYTILACEA.
Family ARClDJi.
Subfamily ARCINiE.
Shell either equivalve or inequivalve, oval, rounded or trapezoidal,
covered with a periostraeum ; ligament spreading over a
considerable external area, or confined to a small depression ;
hinge multi-dentate, the teeth short or lameliiforin; adductor
scars extended, subequal; pallial line simple; interior of shell
not nacreous.
Animal, with the exception of Seapliida, marine; foot large,,
broad, bearing a byssif'erous groove and frequently !\, by^'^us ; the
adductor muscles ju both Valves of about equal size -, siphons
absent; gills oblique, either equal or unequal; palpes simplewithout
posterior appendages.
Distribution. Tropical and subtropical seas, and rivers of
Eastern India and Burma far beyond the limits of tide.