NASSA. 351 



species and N. nitida is not less than between N. incras- 

 sata and 2V. pygmcsa. Kiener's variety of N. reticulata 

 is evidently not our shell : he distinguishes it solely by 

 the spiral striae being less marked. 



N. Si^ 3. N. INCRASSA'TA*/ Strom/ ft\-fr 



Buccinum (Incrassatum), Strom in Kong. Norsk. Vid. Selsk. Skr. iv. 

 p. 369, t. xvi. f. 25. N. incrassata, F. & H. iii. p. 391, pi. cviii. f. 3, 4, 

 and (animal) pi. LL. f. 1. 



BODY yellowish of various shades, closely and minutely but 

 irregularly speckled or marked with black ; there are also 

 some milk-white flakes scattered over different parts : paUial 

 tube cylindrical, very long and flexible, projecting when the 

 animal is in motion, and recurved when it is at rest ; this 

 serves as an auxiliary tentacle or organ of touch, as well as to 

 supply the gills with water : head extremely small, of a pinkish 

 hue: proboscis thicker towards the point: tentacles thread- 

 shaped, rather long, with rounded tips : eyes on stalks con- 

 joined with the tentacles at their outer base, each stalk being 

 nearly equal in length to that part of the tentacle which is 

 above the eyes: foot triangular and expansile, slightly in- 

 dented in front, with a small ear-shaped lobe or flap at each 

 corner, bluntly pointed behind ; tail forked, or furnished with 

 two short flattened prongs or cirri ; in specimens from deep 

 water the foot is largely bilobed behind, but has no point at 

 the tail, which is merely cloven in the middle : odontophore 

 narrow ; [rhachis having the corners incurved and produced 

 in front, edge smooth on each side ; uncinus broad, with a 

 large single-spined tooth at the base. (Loven.)] 



SHELL, although small, stout and thick, opaque, somewhat 

 glossy : sculpture, strong but not prominent, obliquely curved 

 longitudinal ribs, from 15 to 18 on each of the last three 

 whorls, the number decreasing on the upper whorls ; that 

 which margins the outer lip is extremely large and broad ; 

 the ribs are crossed by conspicuous spiral ridges or striae, of 

 which there are from 12 to 16 on the body-whorl, 9 to 11 

 on the penultimate whorl, the number proportionally dimi- 

 nishing upwards; the ridges below the suture are narrow 

 and close together, those in the middle of each whorl bein^ 

 broader and more apart; in some specimens the ridges are 



* Thickened. 



