PLEUROTOMA. 383 



somewhat flattened or shelf-like at the top, and angulated by 

 the ribs ; the last whorl occupies six-elevenths of the shell : 

 suture deep : mouth narrow, compressed and acute-angled 

 above, and broader in the middle ; length nearly four-elevenths 

 of the shell : canal short, straight, and wide, expanding at the 

 extremity in full-grown specimens ; basal notch obliquely in- 

 curved : outer lip flexuous, slightly bent inwards ; edge sharp 

 and muricated by the extremities of the spiral strise : labial 

 notch small and short, situate on the shelf-like ledge at the top 

 of the body-whorl : inner lip retired, finely polished : pillar 

 short and nearly straight. L. 0-275. B. 0-1. 



HABTTAT : Mud among stones, and muddy sand, in 

 10-60 f., Weymouth (Thompson), Exmouth (Clark), 

 Torquay (Battersby and J. G. J.), Plymouth (Barlee and 

 Jordan), Falmouth (Barlee and Hockin), Cornwall 

 (M f Andrew) , Whitburn (Alder) , Dogger bank (Men- 

 nell), Bantry (Barlee), co. Antrim (Waller), Oban, 

 Skye, and Loch Carron (J. G. J., Forbes, and others), 

 Moray Firth (Gordon), Aberdeenshire (Dawson), Wick 

 (Peach), Shetland (M f Andrew and others). Newer 

 tertiaries at Tarento (Philippi). Christiansund, 40-50 f. 

 (Danielssen) ; Bohuslan (Loven, and in 1650 f. Malm) ; 

 Loire-Inferieure (Cailliaud); Arcachon (Fischer); Co- 

 runnato Gibraltar, 8-30 f. (M< Andrew); Malaga (M f An- 

 drew) to Naples (Philippi) on the European coast of the 

 Mediterranean, in 10-50 f., and on the North African 

 coast, in 35 and 36 f. (M f Andrew and Weinkauff); Adria- 

 tic (Brusina); ^Egean (Forbes, fide Reeve, as P. Cycla- 

 densis) . 



Most of the specimens which I received from the late 

 Mr. Clark under this name belong to a dwarf and deep- 

 water variety of P. nebula. The Clavatula brachystoma 

 of Searles Wood appears to be an extinct species. Loven 

 described our shell as Mangilia tiarula. 



