TURRITELLA. 81 



edge (Loven)] : tentacles conical, pointed, slender, and variable 

 in length : eyes small, on bulbs or offsets at the outer base of the 

 tentacles : foot lanceolate, dilated and rounded in front, bluntly 

 angulated and abruptly terminating behind [" grooved below " 

 (F. & H.); sole marked on its hinder portion with a depressed 

 line down the centre (Clark)]. 



Shell forming a slender and elongated pyramid, with a more 

 or less narrow base which is somewhat angulated ; it is solid, 

 opaque, and of a dull hue : sculpture, rather sharp spiral ridges, 

 of which there are 3 on each of the upper whorls, and double 

 that number on the last whorl, besides several intermediate 

 and smaller ribs on the lower whorls, and sometimes also on the 

 upper ones ; the whole surface is covered with fine and close- 

 set indistinct flexuous striae in the line of growth : colour 

 yellowish-brown of various shades, with occasionally darker 

 longitudinal streaks : spire sharply pointed, although the tip 

 is usually broken off: whorls 16-20, convex but compressed, 

 shelving above and below the suture ; they increase very 

 gradually : suture distinct, becoming deeper towards the base 

 of the spire : mouth squarish, angulated above and slightly ex- 

 panding below: outer lip incurved, on the upper side: inner 

 lip reflected over the pillar, and in adult specimens united with 

 the outer lip : operculum dark-horncolour with a tawny coating, 

 composed of about 30 imbricated turns, which are invested with 

 minute and delicate tuberculated threads arranged obliquely 

 and sometimes projecting beyond the margin so as to make it 

 appear spinous; the centre is slightly concave. L. 2 - 25. 

 B. 0-05. 



Yar. 1. nivea. Snowy-white. 



Yar. 2. gracilis. Narrower and more slender. 



Habitat : Sand and mud in 3-100 f., throughout our 

 seas ; gregarious. The 1st variety is not uncommon on 

 the west coast of Scotland and in Shetland, mixed with 

 coloured specimens : I have also dredged it at Exmouth. 

 The 2nd variety is local, and occasionally white ; it has 

 been taken at Torquay with the ordinary kind by Mr. 

 Alder, in Shetland by Mr. M' Andrew and others, in 

 Cork Harbour by Mr. Humphreys, and in Bantry Bay 

 by myself. The latter variety also occurs on the coasts 



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