MULTIVALVES LEPAS. 



LEPAS Acorn Shell or Barnacle. 



DESCRIPTION OF PLATE II. 



■©n* I. — Fam. 1. Fi^. 1. L. Tintinnabulum. — i. L.Clavata. — 5. L. Verruca. 

 f^ '^ Fam. 2. Fig. 3. L. Quinquevalvis. 



Fam. 3. Fig. 2. L. Purpurascens. 



Bi*. II Fam. 1. Fig. 6. L. Mitella — 8. L. PoUicipes. 



Fam.2. Fig. 7. L. Anatifera. 



Shell affixed at the base, and consisting of mani/ unequal erect valves. 



OF the genus Lepas forty-three species are known, 

 and they are in general so well characterized that 

 they cannot be confounded with those of any other 

 genus. 



The exterior of the shell is often varied in shape, 

 covering, and coloring; the usual outline is conical, 

 but in some instances, hemispherical ; which form is 

 acquired by a number of valves being placed perpen- 

 dicularly on a base, broad at the lower margin, and 

 gradually tapering towards the summit, which is clos- 

 ed by other smaller valves, placed nearly horizontally, 

 thereby serving as a lid or covering to the animal 

 within. The perpendicular valves are incapable 

 of motion; the horizontal, on the contrary, are move- 

 able at the will of the animal; which through their 

 medium, performs those functions that are neces- 

 sary to its existence. 



The number of valves which constitute the shell 

 is often very indefinite, their usual amount is six; 

 but the L. palmipes has sometimes only four; and 



