On some new Species of AinpiilhnicuLe. 277 



the assumed absence of the columella, it is no more wanting in 

 this than in any other species of the genus. ^ 



In fact, it only differs from them in the size of the space be- 

 tween the whorls ; and if it is to be placed in the latter genus 

 on that account, several other shells, such as the Staircase Tro- 

 chus, &c. must be also added to it. I am the more astonished 

 at the controversy, as one of the parties has travelled through 

 the Brazils, where this genus is found, and where he might 

 have learnt that the Marisce have gills and breathe air through 

 the medium of water; and every English conchologist knows 

 that the Planorbes on the other hand breathe, by means of a 

 closed bag, free air, which they come to the surface to procure. 

 Consequently these two genera cannot have any affinity with 

 each other, and their resemblance must be purely analogical, 

 and few persons would be inclined to place genera with such 

 different animals side by side. Again, I do not know any of 

 the Planorbes to be banded, as is the case with most of the 

 Ainpullariadce, and colour is not an unimportant adjunct to 

 the natural arrangement of organized bodies, as most zoologists 

 and botanists are well aware. 

 Bithinia lutea. 

 B. testa ovata, lsevi, pallide lutea, pellucida ; anfractibus qua- 



tuor, convexis ; apice obtusa ; columella perforata. 



Ditches, East Indies. Mrs. F. Gray. 



Shell ovate, smooth, pale yellow, pellucid ; the whorls four, 

 rather convex, the sutures distinct ; the apex obtuse as if the 

 first whorl was broken off; the axis with a narrow deep per- 

 foration, axis -j- 3 ^, diameter ^ of an inch. 



Bithinia is a generic name proposed by Mr. Prideaux for 

 the small ovate species of Ampidlariadce which have a shelly 

 operculum and slightly thickened peristome, of which Helix 

 tentaculata may be considered the type. 



Bithinia pusilla. 



B. testa ovata, laevi, alba, hyalina, anfractibus quatuor, con- 

 vexis ; apice subobtusis ; columella imperforate. 

 Ditches, East Indies. Mrs. F. Gray. 

 Shell ovate, smooth, white, hyaline, with four convex whorls 



divided by very distinct sutures, and rather obtuse at the apex; 



the axis is imperforated, axis fo diameter T 2 g- of an inch. 

 I have transmitted both these latter species to the Baron 



Ferussac, who declares them to be as yet undescribed and 



new to him. 



XLVIII. Ana- 



