LIMNiEIN.E. 251 



of a glutinous thread. They deposit their ova, which are 

 enveloped in an ohlong, gelatinous nidus, on the stems and 

 leaves of the weeds which grow around them. The form of 

 their shells varies according to the genus, from the spiral 

 Limncea and Physa to the discoid Planorbis and Segmen- 

 ting and from the slipper- shaped Gundlachia to the 

 linrpet-like Ancylus and the cryptiform Latia. The shells 

 are usually horn- coloured, but in their South -American 

 representative, Chilina, they are ornamented with coloured 

 spots and bands, and, as is frequently the case in fluviatile 

 Mollusks, the apex of the spire is often found eroded. 



Sub-fam. LIMN^EIN^l. 



Shell spiral, more or less elongated, the last whorl large ; 

 aperture oblong. 



Genus CHILINA, Gray. 



Tentacles depressed, angular. Pulmonary orifice pro- 

 tected by a prominent, flattened appendage of the mantle. 



Shell thin, oval, ventricose, with coloured spots and bands; 

 spire obtuse ; aperture oval-oblong ; inner lip thickened, 

 with one or more strong folds ; outer lip simple, acute. 



Syn. Dombeya, D'Orb. Ida, Lea. Potomophila, 

 Swains. 



Ex. C. fluctuosa, Humphrey ', pi. 83, fig. 6. Shell, 

 C. fluctuosa, fig. C, a. 



The species of Chilina inhabit the clear, running streams 

 and rivers of South America, where they are found living 

 on the rocks and stones, or crawling on the mud ; in the 

 rainy season they remain for some months under water, 

 without ever coming to the surface. They seem to represent 



