METAMORPHOSES. 13 



little approximate pair, are normally the posterior of the 

 two pair. According to Milne Edwards, the posterior 

 pair are normally seated outside the anterior pair, and this 

 is the case with those within the lateral horns. 



Larva in the Second Stage. — Notwithstanding the 

 considerable changes, already briefly given, which the 

 larva undergoes during the first two or three exuviations 

 after leaving the egg, all these forms may be conve- 

 niently classed under the first stage. The larva in the 

 Second stage is known only from a single specimen 

 described, figured, and found by Burmeister,* adhering to 

 sea-weed in the midst of other larvae of Lepas in the 

 last stage. In its general shape and compressed form, 

 it seems to come nearer to the last than to the first stage. 

 It has only three pair of legs, situated much more pos- 

 teriorly on the body than in the first stage, and all directed 

 posteriorly ; they are much shorter than heretofore, and 

 resemble rather closely those of the last stage, with the 

 important exception that the first pair has only one ramus. 

 It is this circumstance which leaves no doubt on my mind, 

 that we here have the three pair of limbs, of the first 

 stage, metamorphosed. The body is prolonged some way 

 behind these limbs, and ends in a blunt, rounded point, in 

 which, probably, are developed the three posterior pair 

 of legs and the abdomen of the larva in the last stage. 

 The mouth is now seated some way anteriorly to the 

 limbs, is large and probosciformed, and is, I presume, still 

 destitute of tropin. There are now two closely approximate 

 eyes, but as yet both are simple. The smaller pair of 

 antennae has disappeared. The whole animal was attached 

 to the sea-weed by a (I presume, pair of,) " fleischigen 

 Fortsatz," which Burmeister considers as the prehensile 

 antennae, to be presently described, in an early state of 

 development. I have little doubt that this is correct, for 

 in an abnormal Cirripede of another order, in which 

 the larva appears in the^rs^ stage with prehensile an- 

 tennae, the eggs have two great projecting horns including 



* Beitrage zur Naturgeschichte der Rankenfiisser, s. 16, Tab. i, figs. 3, 4. 



