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colorless, and paucispiral, Adults (with 6-9 whorls) measure 7-10 mm. 
in height. 
Distribution: Yangtze River drainage system in China, 
This species, and the related P, (K,) nosophora and P, (K,) quadrasi, 
are the vectors of schistosomiasis, or the human blood fluke disease, in 
the Orient. P. (K,) formosana has not been directly implicated in trans- 
mitting the human schistosome, but is known to carry a strain which 
infects livestock and probably can carry the human strain. All four species 
are commonly referred to the genus Oncomelania, 
Pomatiopsis (Katayama) nosophora (Robson) 
Plate IV, F 
This species is very similar to P, (O,) hupensis but is smaller, barely 
perforate, and lacks the heavy axial ribs. It is slightly larger and has a 
relatively narrower body whorl than P,. (K,) formosana and P, (K, ) quadrasi. 
The height of its body whorl is 2-3 times that of its penultimate whorl. Its 
color is chestnut brown, Adult shells (with 6-9 whorls) measure 5-10 mm, 
in height. 
Distribution: Japan; central and southern China, 
Pomatiopsis (Katayama) formosana (Pilsbry and Hirase) 
Shell barely perforate, similar to its related species, but without the 
axial ribs of P, (O,) hupensis, and with a body whorl that is relatively 
broader than P, (K,) nosophora, and narrower than P, (K,) quadrasi, The 
height of the body whorl is 4 times that of the penultimate whorl. Color 
chestnut brown to horn, Adult shells (with 6-7 whorls) measure 6-7 mm. 
in height. 
Distribution: Formosa, 
Pomatiopsis (Katayama) Quadrasi (Moellendorff) 
Shell similar to its related species, but smaller, with a relatively larger 
body whorl, imperforate or nearly so, and without axial ribs. The height 
of the body whorl is about 5 times that of the penultimate whorl. Color 
dark horn to chocolate brown. Adult shells (with 6-7 whorls) measure 3-5 
mm. in height. 
Distribution: Philippine Islands. 
