MELANTID-^. 251 



of the whorls. India,, North Australia. P. telescojnum (Ixx, 71) 

 is so abundant near Calcutta as to be used for burning into 

 lime ; great heaps of it are first exposed to the sun, to kill the 

 animals. They have been brought alive to England. (Benson.) 

 In Borneo they are eaten by the natives. 



CERiTHiDEA, Swains. Shell turriculated, longitudinally ribbed ; 

 whorls numerous; summit of spire more or less decollated, aper- 

 ture rounded, slightly slit anteriorly', outer lip expanded, thick- 

 ened, broadly rounded below and usually produced into a beak 

 crossing the sinus to the left. Eye-pedicels long and thick, 

 connate with the tentacles nearly to their tips. Inhabit salt 

 marshes, mangrove swamps, and the mouth of rivers ; they are 

 so commonly out of the water as to have been taken for land- 

 shells. Mr. Adams noticed them in the fresh waters of the 

 interior of Borneo, creeping on pontederia and sedges ; they 

 often suspend themselves by glutinous threads Distr. — India, 

 Ce3don, Singapore, Borneo, Philippines, Port Essington. P. 

 decollatum, Linn. (Ixx, 72). P. obtusum, Lam. (Ixx, 73). 



piRENELLA, Gray, 1847. Shell turriculated, whorls granulated, 

 or with irregular ribs and varices ; aperture rounded ; anterior 

 canal short ; inner lip simple, outer lip thin, sinuous. P. mamil- 

 latum, Phil. There is a fossil species in the Laramie beds, U. S. 



SANDBERGERiA, Bosquet, 1861. Proposed for a number of ovate 

 species, from the tertiary, having a very broad, shallow, but 

 slightly produced canaliculation in front. The operculum is 

 said to be paucispiral, and if this be actually the case, the divi- 

 sion may be maintained , otherwise the shells are not readily 

 distinguishable from Cerithidea. P. antecedens, Stol. 



ESCOFFIERIA, Fontannes, 1881. P. Fischeri^ Font. Tertiary; 

 France. 



Family MELANIID^. 



Shell spiral, turreted ; with a thick, dark epidermis ; aperture 

 often channeled, or notched in front ; outer lip acute ; operculum 

 horny, spiral. The spire is often extensively eroded by the 

 acidity of the water in which the animals live. 



Animal with a broad, non-retractile muzzle ; tentacles distant, 

 subulate ; eyes on short stalks, united to the outer sides of the 

 tentacles ; foot broad and short, angulated in front ; mantle- 

 margin fringed ; tongue long and linear, with a median, and three 

 lateral series of hooked multicuspid teeth ; gill composed of 

 rigid, cylindrical plates. Often viviparous. Inhabiting fresh- 

 water lakes and rivers throughout the warmer parts of the world 

 (except North America). 



The Melanians are fluviatile mollusks, closely related through 

 Potamides, with the Cerithiidae. They possess the fringed mantle- 

 margin characteristic of the latter family, and are thereby imme- 



