MELANIA 



891 



Glassifleation. — There are two tribes : — 



A. Creeping forms, with foot flattened ventrally — Platypoda. 



B. Free-swimming forms, with foot flattened laterally — Heteropoda. 

 We are concerned with the Platypoda. 



Tribe Platypoda. 

 Definition. — Taenioglossa with the characters given above. 

 Classification. — There are some fifty-five families, of which we are interested 

 in the Melaniidae only. 



Family Melaniidae Gray. 



Definition. — Platypoda with spiral shell and elongated spire. 

 Operculum horny. Foot short. Mantle border fringed. Vivi- 

 parous. Fluviatile. 



Classification. — Several genera. 



A. Shell long: — 



I. Shell turriculated, aperture enlarged anteriorly — 

 Melania. 



II. Spiral very long, aperture notched anteriorly — Faunus. 



B. Shell short, thick, and aperture rounded — Other genera. 



Melania Lamarck. 

 Synonyms. — Thiara Mergele ; Pyrgula Crist. 



Definition. — Melaniidae with turreted shell, acute apex, whorls 

 ornamented with striae or spires; aperture 

 oval, pointed above ; outer lip sharp, 

 sinuous. Operculum subspiral. 



Type Species. — Melania hastula Leach. 



Remarks. — Some 400 or more species 

 distributed throughout Southern Europe, 

 India, the Philippines, Japan, and the 

 Pacific Islands. Distinct groups in the 

 Southern United States. 



According to Nakagawa, Melania ohliquogranosa Smith and M- 

 lihertina Gould are intermediate hosts of Paragonimus ringeri 

 Cobbold, but Kobayashi believes that the cercarise seen by Naka- 

 gawa in these molluscs are not those of P. ringeri. 



Blandfordia Adams, 1863. 



Definition. — Melaniidae with ovate conical 

 shell, apex truncated. Aperture elliptical, 

 peristome continuous, operculum subspiral. 

 Rostrum elongated. Tentacles very short, 

 eyes sessile. Foot large; divided into two 

 parts by a transverse sulcus. 



Type. — Blandfordia striatula Menke. 

 Other Species.— 5. hensoni Kdzm?,; B, japo- 

 nica Adams; B. pyrrhostona Cox; B. viri- 

 descens Carpenter. 

 We are only concerned with B. japonica, which is the carrier of 

 Schistosomum japonicum. 



Fig. 464. — Bulinus 

 contortus (p. 893). 



Fig. 465. — Blandfordia 

 japonica Adams, 

 1861. The Carrier 

 OF Schistosoma 

 Japonicum. 



