262 MARSHALL: ADDITIONS TO 'BRITISH CONCHOLOGY.' 



the thickened outer lip, tuberculated aperture, and enam- 

 elled pillar of the largest. The young of the same size 

 have none of these characteristics, and the base is more or 

 less angulated. The specimen 'from Clark's collection, 

 not half an inch long,' mentioned by Jeffreys, belongs to 

 this variety. 



Defrancia linearis var. alba Marsh. Pure white. Guernsey, 

 20 fathoms ; Scilly, 40 fathoms ; Land's End. Rare. 



Pleurotoma costata var. coarctata Forbes. I know of no 

 reason why Jeffreys did not recognise this variety. It in- 

 habits our northern coasts, and is double the size of the 

 southern form, with a longer and more tapering spire. It 

 is described and figured in Forbes and Hanley's work. 

 Jeffreys' description is taken from the northern form, judg- 

 ing from the dimensions he gives ; this averages four lines 

 in length, and the southern form two-and-a-half lines. 



P. nebula var. fusiforme Marsh. Shell larger, the same 

 length as the var. eIo?igafa, with a shorter spire and longer 

 body-whorl ; colour ashen-grey, with streaks of pale-brown 

 between the ribs ; these ribs are inconspicuous, almost dis- 

 appearing on the body-whorl ; spiral sculpture finer, and 

 uniform; suture much shallower. In shape, sculpture, and 

 proportions, this is more like P. Icevigata than nebula, but 

 it has not the characteristic strap-like band encircling the 

 upper part of the whorls. In the 'Annals' for December, 

 1875, I referred this variety to the var. elongata, as from the 

 Doggerbank, in 40 fathoms ; but that variety has a long 

 spire and short body-whorl, the reverse of this, besides 

 other differences enumerated above. I have it also from 

 the Minch in 30 fathoms. 



P. rufa var. praelonga Marsh. Spire much produced; whorls 

 9 ; ribs slight or altogether absent, especially on the lower 

 whorls. Lengthy three-quarters of an inch. Guernsey, 20 

 fathoms, rare. 



J.C, vii., Oct. 1893. 



