153 



according to the observations of M. Quoy, is widely open in front ; no 

 basal notcli or channel is therefore needed in the shell for the passage of 

 that organ, which leads in most of the carnivorous tribes to the respiratory 

 cavity in a more concealed situation. 



Among the few species known of this genus, the P. maculosa is the largest 

 and most elongated ; the P. dolabrata is common in the Eastern Seas ; 

 the P.ventricosa is a fine species from New Holland, and the P.plicata, 

 chiefly remarkable for its longitudinally plicated ribs, of which there is no 

 indication in the before-mentioned species, is, according to Lamarck, from 

 Mauritius. 



1. cincta, Reeve. 



2. corrugata, Lam. 



3. dolabrata, id. 



4. glans, Reeve. 



Species. 



5. gracilis, Brocchi. 



6. maculosa, Lam. 



7. plicata, id. 



8. solida, Sow. 



9. sulcata, Nutt. 



10. terebellum, Lam,. 



11. ventricosa, Guerin. 



Figure. 



Pyramidella maculosa. PL 14. Pig. 73. Shell, showing its elongately 

 pyramidal growth, plaited columella, and small aperture. 



Genus 2. TORNATELLA, Lamarck. 



Animal; unknown. 



Shell ; cylindrically oval, with a very short spire, mostly trans- 

 versely striated, never ribbed, columella strongly two-plaited, 

 sometimes with one plait only, aperture oblong, reaching nearly 

 to the top of the body-whorl. 



Although shells of this genus are by no means of rare occurrence, it 

 does not appear that the animal has been yet described. Their typical 

 form is the reverse of that of Pyramidella ; instead of having a small 

 aperture and long drawn out spire, the shell is of an oval Bulla form, has 

 a very short spire, and an oblong aperture reaching nearly to the summit 

 of the body whorl. The plait or plaits of the columella range obliquely, and 

 are strongly developed. 



Linnaeus placed the Tornatellce among his Volutes ; Bruguiere observing 

 the absence of any notch at the base, transferred them to the genus Bidi- 

 mus, where they became associated with a numerous tribe of uncongenial 

 habits, which the sagacity of Lamarck readily detected. They constitute 



