MITRES. 89 



short peduncles ; the respiratory siphon is small, and not 

 dilated into lobes at the base, and the trunk is capable of 

 remarkable elongation ; lastly, their habits vary, and they 

 differ in geographical Hmits. 



Three hundred and thirty species, as already noticed, 

 pertain to the genus llilra; and in these, what infinite 

 variety ! No two individuals are alike. Some are beau- 

 tifully varied and adorned, others are neatly finished. It 

 seems, however, that the constructing inhabitant, although 

 loving to adorn his mansion, is a creature of limited sensi- 

 bility, and that his powers of locomotion are necessarily 

 restrained by the overbalancing proportions of his shell ; or 

 else, that being furnished with the means of lengthening his 

 trunk to an extent not assigned to any other genus, and 

 having the extremity terminated by a kind of dentated 

 chewing apparatus, by aid of which he is enabled to capture 

 his food with little apparent effort, and without altering his 

 position, he prefers to devote his energies to forming an 

 ample dwelKng, and adorning it with the most exquisite 

 specimens of art. 



The Mitra Norrisii, or Norris^s Mitre, dedicated by Mr. 

 Eeeve to that esteemed patron of the natural sciences, 

 whose magnificent collection of Mitres is, perhaps, un- 



