82 INTRODUCTION TO CONCHOLOGY. 



shell;, are smooth and polished^, forming what has been 

 termed 2. papilla ^ before either a pattern or sculpture is de- 

 veloped. Mr. Eeeve has adduced various instances of modi- 

 fication in the apex : lie mentions that such are uniformly 

 accompanied with distinctive features in other parts of the 

 shelb serving to characterize groups,, and divide the genus 

 into subgenera or sections ; that, further, except in the small 

 V. ahjssicola, the only living representative of a group of 

 fossil species found abundantly in the Tertiary beds of Great 

 Britain, there is no transverse sculpture in this geuus. 



Linnaeus included under genus Voluta all shells having 

 a row of plaits winding round the columella, without con- 

 sidering the nature or habits of their animal occupants. 

 Conchologists of the present day have rectified this error by 

 separating such as were originally, and in the infancy of 

 science, comprehended under the same generic type. 



The occupant of the Voluta differs little from that of the 

 Cpnhium, except in being smaller, less expansile, and more 

 richly tinted. It has the same peculiar lobed dilation 

 of the respiratory siphon, and the eyes, as in that genus, 

 are rather distant from the tentacles. The living species 

 hitherto figured are brilliantly coloured ; but there is no 

 similarity between the colour or pattern of the animal and 

 its shell. 



