66 



POPULAR CONCHOLOGY. 



proper position by a group of barnacles ; these had pro- 

 bably attached themselves to the back of the shell of the 

 Pyrula at an earlier stage ; and as the latter increased in 

 size, at length filled the place that should have been occupied 

 by the inner lip, which, on meeting with this interruption, 

 diverged from its course, and was thrown over the bar- 

 nacles. Had the shell not been taken until a later period, 

 there can be little doubt that the animal would have at 

 length destroyed the barnacles, or completely hidden them 

 from view, although it would appear that it had not 

 the power to remove them by absorption while they re- 

 tained their vitality.* 



Murex. Lin. — Shell oblong, spire rather short; canal 

 generally long, sometimes con- 

 tracted, and sometimes par- 

 tially closed ; varices three or 

 more on each whorl, spiny, 

 foliated or rough, and con- 

 nected with those of the whorl 

 above ; aperture round and 

 small. Animal, with a broad 

 lunate flattened head, flanked 

 by two tentacula having stout 

 bases, bearing the eyes at one 

 half or two thirds of their 

 length ; proboscis retractile, 

 moderately long ; tongue armed 

 with transverse rows of teeth, 

 each row composed of a central 

 transversely and quadrat ely 

 oblong axile tooth, with three 

 recurved denticular processes, 



Murex tenuispina. 



