TROCHUS. 511 



T. MoNTAGui, Gray. 



Produced-conical, imperforated, small ; whorls more or less 

 rounded, with only about five or six distinctly separated spiral 

 costellae, and no marginal belt : the interstices striated longitu- 

 dinally ; painting usually consisting of brown longitudinal lines 

 on a yellowish white or ash-coloured ground, which are often so 

 interrupted in the interstices, that the spiral costellse appear 

 articulated. 



Plate LXV. figs. 10, 11. 



Trochus Mo7itac/ui, Gray in Index Testae. Suppl. pi. 6, Troch. f. 43. — Brit. 

 Marine Conch, p. 255, f. 18. 

 „ striatus, FoRBES, Malac. Monens. p. 22, animal. 



This plain-looking little shell has a more elongated form 

 than our other British Trochi. It is of a produced 

 conical figure, with the lateral outlines straightish, but 

 more inclined to convexity than retusion. It varies in 

 strength and lustre, but is never highly polished, and is 

 composed of seven slightly convex volutions, whose elon- 

 gation is by no means rapid (especially in the lower ones, 

 which are rather high, their breadth above being only 

 double their length), that are very abrupt in their declina- 

 tion, and terminate in a small but obtuse point ; a slight 

 disposition to angularity sometimes exists beneath the 

 suture upon the body-whorl. Five narrow and somewhat 

 rounded costellae spirally encircle them ; whose intervals, 

 which are broader, or at least as broad as the belts, are 

 obliquely and closely traversed by most delicate longitu- 

 dinal raised striulee, that occasionally (and possibly always 

 in the finer preserved individuals) cross the costellpe like- 

 wise ; a precisely similar sculpture is continued upon the 

 base of the shell. There is no marginal belt, but two 

 costellse often approximate at the outer margin of the 



