^6 



My friend, Hon. Edward Chitty, informs me that he has detected 

 an operculum in Geomelania, and that he has some additional species. 



Descriptions of supposed new species of Marine Shells, which 

 inhabit Jamaica. By C. B. Adams, Jan.. 1850. 



Marginella nivea. Shell obovate, white, translucent, with nu- 

 merous spots of opaque white : smooth and sltining : apex acute : 

 spire small, short, vitreous, wholly opaque white : whorls about three 

 and one-half: aperture long, effuse above: varix stout, produced to 

 the apex : columella with four prominent plaits. 



Mean divergence about 100'' ; length of spire .06 inch ; total length 

 .37 inch ; breadth .22 inch. 



This species resembles 31. jn-iiinosa Hinds, but is much smaller, 

 more regularly obovate, the spire is shorter, and the coloration is dif- 

 ferent except in the opaque white spots. 



Marginella alba. Shell obovate, wide: pure opaque white: 

 smooth and shining : spire concealed, wdth a shallow pit in its place : 

 labrum well excurved in its upper part, produced to the summit, 

 rather sharp edged, thick, smooth within : columella with four or five 

 plaits, of which the upper one or two are inconspicuous. 



Length .205 inch ; breadth .13 inch. 



Marginella abbreviata. Shell oblong, but much contracted 

 anteriorly : white : smooth and shining : spire very short : apex rath- 

 er obtuse : whorls about three and one-third: labrum incurved and 

 contracting the aperture : varix produced a little way on the spire : 

 columella with four plaits of which the upper one is small. 



Mean divergence about 90° ; length of spire about .04 inch ; total 

 length .22 inch ; breadth .11 inch. 



This shell resembles M. luctea Kr., but is much shorter, and is 

 broader at the top of the last whorl ; in j\I. lactea the varix extends 

 farther on the apex. 



Marginella fluctuata. Shell obovate : whitish, with very 

 narrow longitudinal strongly waved lines of brown, which extend from 

 the summit to the anterior extremity, and which, being more conspic- 

 uous at the summit and at intervals, form spiral series, a little above 

 and a little below the greatest convexity of the shell : spire entirely 



