PLEUROTOMA. 379 



found in the Bute deposit by Mr. Crosskey is erroneous. 

 Its present distribution is mostly southern — although 

 Loven and Malm have dredged it in the south of Sweden, 

 and Sars has recorded it with doubt from Oxfjord — 

 Atlantic coasts of France, Spain, and Portugal, from 

 Boulogne to Gibraltar ; Teneriffe (M*^ Andrew) ; Mediter- 

 ranean, Adriatic, and iEgean : depths 2-40 f. 



This elegant shell differs from P. striolata in being 

 more slender, and highly polished ; the ribs are not an- 

 gulated at the top, nor is the spire turreted ; the surface 

 is smooth ; and the linear markings are very peculiar. 

 My finest specimen (for which I am indebted to the 

 kindness of Dr. Batter sby, who dredged it at Torquay) 

 is three-quarters of an inch long. 



It appears to be the Mangelia striolata of Bisso, P. 

 Villiersi of Michaud, P. gracilis of Scacchi, and P. nu- 

 perrimum of Tiberi. 



3. P. costa'ta"^, Donovan. 



Murex costatus, Don. Br. Sh. iii. pi. xci. Mangelia costata, F. & H. iii. 

 p. 485, pi. cxiv. A. f. 3-5, and (animal) pi. ER. f. 4. 



Body clear white, with a bluish tinge, more or less closely 

 speckled with light purplish-brown or yellow, or with irregular 

 flakes of milk-white : imlUal tube cylindrical, rather long and 

 flexible, exhibiting a notch-like fold at the opening : tentacles 

 rather short, with bulbous tips, doubled in thiclmess for the 

 lower half by the eye-stalks : eyes rather large, placed on 

 swollen terminations of the stalks : foot elongated, narrow, and 

 thick, in front truncated, gently curved, or slightly indented 

 with small angular corners, attenuated and finely pointed be- 

 hind ; when the animal is at rest, the sole is strangulated or 

 divided across in the middle : [odontopliore, pleural spine 

 strong, with the head or top folded back, and the side indented 

 and gaping or incurved. (Loven.)] 



Shell agreeing in many particulars with that of P. atte- 



* Ribbed. 



