163 



CHAPTER XXVII. 



AVENTLETRAP. — FORMATION OF THE RINGS, OR VARICES. — BRITISH 

 SPECIES OF SCALARIA. 



SCALARID.^. 



ScALARiA. — While the few British species of this genus 

 possess shells far Inferior in size and beauty of form to that 

 most elegant of spirals, the Scalaria pretiosa, and some 

 other exotic kinds, they make up the deficiency in formal 

 grandeur by a display of extra taste in the colouring of their 

 turreted whorls. Contrary to the general habit of British 

 mollusca, the shells of Scalarice vie, in the brightness of 

 their tints, with any of their foreign brethren. The well- 

 known ' Wentletrap,' Scalaria pretiosa, so celebrated for 

 the extravagant prices formerly paid for specimens by col- 

 lectors, has the beauty of its shell greatly increased by the 

 whorls being separated from each other, each ridge, or varix, 

 forming a distinct ring round the circumference. 



