THE LERNALA. ^Cg 



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 Cirripcdid) 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. Ange and other foreign naturalists. The engraving of 

 Lcpas anatifera on the next page gives an idea of the shape of one 

 great division of the Cirripcdia — 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 



