THE LERNjEA. 
469 
developed, but not increased in number ; the eye is distinct, and 
there is a peculiar tortuous tube running from it downwards 
besides a digestive sac. In the course of a very short time a 
metamorphosis occurs ; the outer integument is loosened by the 
formation of a second beneath it, which encloses a body altered 
in its shape and in the number and nature of its appendages. 
The body of the new form has six legs (five if the double one 
is counted as one), an elongated abdomen, antennae, and the 
eye ; and the first three extremities are furnished with prehen- 
sile organs, whilst the last are natatory. 
Owen, quoting Nordmann, states that in the parasite of the 
perch the antennae probably seem to indicate to the freely swim- 
ming creature its appropriate object, to which it then proceeds 
to attach itself. The second pair of legs increase in size, and 
their terminal hook enlarges ; the third pair lengthen and unite 
together to form a circular cartilaginous sucker. The first pair 
of feet form the mandibles. This is the last metamorphosis, 
and the Lerncea becomes stationary. The two sexes are alike in 
their young and locomotive state ; the male has shorter and 
thicker second legs, and is not hung up for life, as he has to 
seek his mate, but the hind natatory legs disappear in both. 
The metamorphoses of the barnacle tribe (the Cirripedid) are 
quite as decided and as extraordinary as those of the other Crus- 
tacea. They have been specially studied by Spence Bate, by that 
most accurate and philosophical observer, Charles Darwin, and by 
Martin St. Auge and other foreign naturalists. The engraving of 
Lepas anatifera on the next page gives an idea of the shape of one 
great division of the Cirripedia — the stalked. This class is divided 
into pedunculated or stalked, and sessile or unstalked kinds ; the 
first are represented hanging on to pieces of wood, and the last may 
be seen encrusting nearly every rock and piece of timber on most 
parts of the sea-coast, and are something like acorns in shape. 
Neither the pedunculated nor the sessile kinds ever move from 
their fixed position, and the only evidence of life presented by 
them to the ordinary observer is the occasional projection from the 
end of the shell of delicate fringed “ cirri,” which thresh the water 
in one direction. The cirri are represented in the large engraving 
like so many feathers projecting from the side of the shell of the 
