44 
LEPAS. 
cipal essential characters, being multivalve, and 
parasitical'; and the species pass gradually from 
one conformation to the other in so connected a 
series, that it would seem needless, and indeed de- 
structive of simplicity and order, to separate or dis- 
arrange them. The aperture in the conical divi- 
sion increases proportionably to the growth of the 
shell, by means of the extension, in width, of the 
triangular parts between the valves. The pedun- 
cled species are called Barnacles, from a strange 
prejudice formerly entertained, that they were 
transformed into geese ; originating perhaps in 
their feathery tentacula, and in their being 
observed moving about on their long flexible tubes 
above the surface of the water. Both divisions are 
invariably attached to extraneous substances, 
usually in groups. 
The genus takes its name either from Xscrag, the 
rockj to which the shells adhere, or from Xscrag, the 
denomination bestowed by the ancients on the 
family of Patellae, on account, probably, of the 
sca/e-like manner in which they are adherent. 
