50 CORBULID^E. 



curved ; rostral prolongation considerable, much more attenu- 

 ated than in the other species : beaks small and mammillary ; 

 umboues by no means prominent ; dorsal area narrowly exca- 

 vated on the posterior side : cartilage orangecolour, contained 

 in a triangular receptacle which shelves outwards : hinge-line 

 straight : hinge-plate narrow and slight : teeth, an extremely 

 minute tubercular cardinal in the left valve, and a strong 

 erect and triangular lateral in the right valve on the posterior 

 side : inside glossy, with a rib on the posterior side : muscular 

 scars well marked ; anterior irregularly oblong, posterior tri- 

 angular. L. 0-25. B. 0-415. 



Var. lactea. Shell milk-white, more glossy, transparent, 

 and delicate, having only two ribs on the posterior angle, 

 besides those on the rostral process. 



HABITAT : Loch Fyne, 40-70 f., with the last species 

 (M f Andrew and Barlee) ; Cumbrae, Firth of Clyde 

 (Robertson) ; Skye and Shetland (Barlee and J. G. J.) . 

 The variety was dredged by me on a sandy bottom, in 

 78 f., from 40 to 50 miles east of the Whalsey Skerries, 

 Shetland. Upper tertiaries of Greece (Deshayes) ; 

 Antwerp (Nyst) ; Guise-Lamotte, France (De Koninck) ; 

 Calabria (Philippi). It inhabits the coasts of Scandi- 

 navia at depths ranging between 10 and 100 f. (Loven 

 and others) ; Carthagena, in 30 f., and Gibraltar, in 45 f. 

 (M f Andrew) ; Provence, in 60 f. (Martin) ; Gulf of 

 Genoa, in 25 f. (J. G. J.) ; Adriatic (Chiereghini) ; 

 Naples (v. Martens) ; JSgean, in 20-185 f. (Forbes) ; 

 Malta, in 40 f., Gulf of Tunis, in 35 f., Madeira, in 

 18-24 f., and Teneriffe, in 20-35 f. (W Andrew). 

 Specimens dredged by the late Professor 1 Barrett in 

 deep water at Jamaica are scarcely distinguishable from 

 those of the North Atlantic. 



This exquisite shell cannot well be mistaken for 

 N. abbreviata \ tbeir shape, sculpture, and dentition are 

 very different. 



Nyst seems to have been the earliest describer of it, 



