MULTl VALVES. LEPAS. 5 



The perpendicular valves are capable of no motion; 

 whereas, on the contrary, the horizontal ones are movea- 

 ble at the pleasure of the animal; who, through their me- 

 dium, performs those functions which are necessary to its 

 existence. 



This genus is frequently (though erroneously) called 

 — Balanus, from the circumstance of some few of its spe- 

 cies bearing an affinity to an acorn; jbutthe resemblance 

 is by no means general, for, in most instances, no two ob- 

 jects can be more dissimilar than the Lepas and the 

 acorn: however, it would prove no easy task to class any 

 of the species among the other genera of Midtivalves, for 

 the conical, pyramidal, or sugar-loaf shape of the Lepas, 

 will always serve as a sufficient mark of distinction. 



Besides ^A hich, the Lepas is never found in the indepen- 

 dant or isolated state that most other shells are ; on the 

 contrary, all its species are known to affix or attach them- 

 selves by their base or stalk to other bodies ; they adhere 

 in clusters or groups, to rocks, coral-reefs, ships' bottoms, 

 and shell-fish: even fish themselves, while swimming, 

 are not exempt from their encroachments, as for in- 

 stance, the whale, phalaena-boops, and others, are fre- 

 quently found laden with them ; and even turtles and 

 tortoises are often encrusted with groups of the Lepas 

 species; it would therefore appear, that the genus is 

 merely capable of motion, and in case of their being 

 transported from one place to another, it is to the exer- 

 tion of other bodies that they must be indebted for their 

 migration. 



The exterior of the shell is often varied in form, cover- 

 ing, and coloring; the usual contour or outline is, how- 

 ever, like the frustrum of a cone or conoid; in others, 

 like that of a pyramid, and, in some instances, parabolical, 



