ASSIMINIA. 69 



body with a subcarinated zone in the centre ; aperture obliquely ovate ; outer lip 

 thin and sharp at the edge ; pillar-lip narrowly reflected, with a slight slit 

 behind. Found at Dunbar by General Bingham." 



We doubt the maturity of this shell. 



The Nerita pellucida and alba of Adams (Trans. Linn. See. vol. iii. p. 67, 

 copied in vol. viii. p. 227, and in Turt. Conch. Diction, p. 127, &c.) are possibly 

 the fry of Lacuna^ but their description is by far too meagre for identification. 



ASSIMINIA. Leach, Grav. 



Shell ovato-conical, solid, with a more or less produced 

 spire, smooth or obscurely striated ; mouth ovate, peri- 

 treme entire, outer lip sharp-edged, columellar lip ap- 

 pressed. Operculum corneous, ovate, of a few rapidly 

 increasing whorls. 



Animal having a muzzle-shaped head, with two rather 

 short tentacula, bearing the eyes on their tips ; no neck- 

 lobes ; operculigerous lobe without filamentary processes. 

 Foot rounded at both ends. Lateral elements of the 

 tongue (as described by Loven) dissimilar ; all with den- 

 ticulated incurved apices ; median denticle with extended 

 lateral crura and a prominent basal process. 



This curious genus is remarkable among its tribe for 

 the position of the eyes at the end of the tentacles. 

 The question has been discussed, whether these tentacles 

 are to be regarded as sustentacula only, or as vihracula 

 and sustentacula united. The latter view, which has been 

 maintained by Mr. Gray, seems to us that which most 

 nearly approaches the truth. 



The Assiminia are mostly inhabitants of brackish 

 water. Species have been discovered in many parts of 

 both the old and new worlds, and many, owing to the 

 difficulty of determining them without a knowledge of 

 the animal, have probably been overlooked. 



