2/0 The Journal of the Indian Archipelago. 



" The Parmaphora or duck's-bill Limpet is found here, though by 

 no means a common shell, it is like a Patella, flattened and elongated, 

 the anterior edge always widely notched, apex slightly recurved, 

 length from one to two inches, colour white ; the body of the animal 

 is much more bulky than the shell, and the mantle is so capacious, 

 that it covers the whole shell except the apex, which enables it 

 in some degree to elude search, as it appears more like a pulpy or 

 spongy mass than a shell ; when touched, the mantle stains the hand 

 a dark-purple colour. 



" There is a species of Planorbis, or shell allied to Planorbis, found 

 here in pools of freshwater, being the only species of Singapore 

 shell that is found solely in freshwater ; the outer whorl is little 

 more than a quarter of an inch in diameter, aperture of the shell 

 more diagonal than is usual in Planorbis ; so that when the animal 

 moves on a plain surface, the convex side of the shell is always 

 uppermost : whereas the animal of Planorbis is described as carrying 

 its shell erect, or with the diameter perpendicular ; colour of the 

 shell pale-amber, no operculum, animal nearly black, mouth ver- 

 tically cleft, no perceptible neck, (in the animal of Planorbis, the 

 neck is said to be elongated,) eyes at the base of two blunt tentacula 

 in which also it differs from Planorbis, which is commonly described 

 and figured as having two subulate tentacula : the animal possesses, 

 in a considerable degree, the power of gliding through the water, 

 apparently in search of food, with its shell entirely submerged, and 

 its smooth foot in close apposition with the surface of the water, 

 locomotion being effected, by causing the flat part of the shell to act 

 on the water in the manner of a fin, the head of the animal being 

 at the same time directed forward so as to regulate its movements ; 

 the animal does not occupy so much as half the shell, and the re- 

 maining space frequently contains air, which the inhabitant has the 

 power of expelling at pleasure. 



" The genus ' Natica,' of which there are several elegant species 

 in Singapore, is known from the ' Nerita' or ' hoof shell,' by being 

 umbilicated, more rounded in form, and the interior not toothed, the 

 shell has been also described as having no epidermis, to this rule 

 however, there are marked exceptions, two of the species, native here, 

 having a strongly adherent epidermis. 



