= G64 = 
Family THIARIDAE 
This is another widely distributed family of aquatic operculate snails of 
considerable medical importance. Their shells are similar to the 
pleurocerids, but their methods of reproduction are quite different. Several 
of the Oriental species are the principal vectors of human lung and liver 
fluke diseases. 
Melanoides tuberculata (Muller) 
Prate IV, E 
Shell similar to Semisulcospira libertina, but narrower, with smaller 
aperture, having more rounded whorls with impressed sutures, more con- 
spicuous spiral lirae, and often transverse ribs onthe spire whorls. In 
some localities, the shells are marked with transverse reddish-brown 
streaks. Uneroded adults (with 9-12 whorls) measure 30-50 mm, inheight, 
Distribution; Southern China, Formosa, Philippines, East Indies. 

This species is a first intermediate host of the human liver fluke. It is 
sometimes placed in the genus Thiara, 
Tarebia granifera (Lamarck) 
Plate lv, 
This species is similar to Semisulcospira libertina and Melanoides tuber- 
culata but has shouldered, flat-sided whorls with impressed sutures, is 
sculptured with many spiral rows of small beads rather than lirae, andhas 
a larger aperture. Color chestnut - to olive-brown. Uneroded adults (with 
9-12 whorls) measure 30-50 mm. in height. 
Distribution: Formosa, Philippines, Micronesia, Melanesia, East Indies. 
This species is a first intermediate host of the human lung fluke. It is 
sometimes placed in the genus Thiara 

Subclass PULMONATA 
Order BASOMMATOPHORA 
Family LYMNAEIDAE 
This and the following family, the Planorbidae, include aquatic lung 
breathers that lack opercula. Both families are world-wide in distribution 
and contain several medically important species. Of chief importance, all 
