45a. 
45b. 
46a. 
46b. 
A7a, 
47b. 
48a, 
48b. 
49a. 
49b, 
50a. 
50b. 
Billa. 
51b. 
52a 
52b. 
53a. 
53b: 
54a, 
54b. 
= 60n2 
African*in) OFIGIN: 6... s6s sce e sre ese see oe oe oe OOMphalamagboOtssiva 
West Indies and South enerie an 
INTO TIGL A Meares csp wrckslciaus Gisia eieualevetels ossesee. or lanorbinalplabmata 
Animal with an Sperone (acover 
to close aperture of shell); 
fresh-water inhabitants. ae Pn es Se eae ees ee Re eh AMA le eee TT 
Animal without an aoe ines lana 
or fresh-water inhabitants..... wegen er otsuenc Siayich eile RS ed Shay Sanaa uals EO EE 
Shelllarge, adults 25mm. (1 ae or 
more inheight; operculum paucispiral, 
with the nucleus nearthe base...... PMO sno soe oreoode ic ocone Be 
Shell medium to small, adults less than 
15mm. (3/8inch); operculum paucispiral 
orconcentric, the nucleus alittle distance 
from the base. Sienelstoietaietanetala Wooo meer eo ooo cee Sooo Sl 
transverse furrows, making them appear 
aSerows) Of beads)... «sc, «, «, « «jareweel shalere steleie Byers! o/s) pe ADeDial panied 
Spiral ridges onthe shell not intersected 
by transverse furrows, but continuowsy i. Jiesesl occ so sects is) ere eee oe 
Whorlstwellxoundeds ie. ois «ss, sce « COO . Melanoides tuberculata 
Whorls flat-sided, or hae 
slightly rounded... sc... «0.0 soe seas sDemMisulecospinaylibertina 
Shell usually with Peed Bote All eee 
operculum thick, calcareous, and 
concentric, arith a small pabeedteals 
Spiral smile ws jcc usieseq eis eee o.-.e...-rarafossarulus manchouricus 
Shell without spiral ridges; 
operculum thin, translucent, 
colorless and Semensneal 7. eyed eae = teioks Binvciacicn 20 
Whorls withtransverseribs.... Paratieeane (Gucamelanis) hupensis 
Whorls without transverse ribs ........ deb, did tettetton etetere tA ae 
Body whorl proportionately large in 
both height and width, its height five 
times that of the penultimate whorl... Pomatiopsis (Katayama) quadrasi 
Body whorl proportionately smaller, 
making the shell appear more slender, its 
height less than five times that of the 
penultimate whorl’. 23.20-1<. lic wed Syste ov aye) ane) pele lok oyeiter shehanoneneleta tel femen ene meeeS 
Height of body whorl about four times 
that of the penultimate whorl......Pomatiopsis (Katayama) formosana 
Height of body whorl two to three times 
that of the penultimate whorl...... Pomatiopsis (Katayama) nosophora 
Spire partly broken off in adult shells Rumina decollata 
Spire normally not broken off...... Sei Bele Sh Sheile tok oie Eucllo ML ONS MI OR Moo eet oD 
