METAMORPHOSES OF AKTMALS. 



355 



a 



four or five inches, and having excavated a sort of cell, is 

 soon changed into a chrysalis or nymph (6). At the usual time 

 in the spring it bursts the skin, and appears in its perfect state, 

 under the form of a moth (d). In this species, however, 

 only the male has wings. The perfect insects soon pair, 

 the female (c) crawls up a tree and having deposited her 

 eggs, dies. 



553. 



Transform- Fig- 370. 



ations no 

 less remark- 

 able are ob- 

 served 

 among the 

 Crustacea. 

 The meta- 

 morphoses 

 in the class 

 cirrhipoda 

 are es- 

 pecially 



striking. It is now known that the barnacles (Balanus), which 

 have been arranged among the mollusca, are truly crusta- 

 ceans ; and this result of modern researches has been deduced 

 in the clearest manner from the study of their transformations. 

 Figures 3/0, a -f, represent the different phases of develop- 

 ment of the duck-barnacle (Anatifd) . 



554. The Anatifa,like all Crustacea, is reproduced by eggs, 

 specimens of which, magnified ninety diameters, are repre- 

 sented in fig. 3/0, a. From these eggs little animals issue, 

 which have not the slightest resemblance to the parent. They 

 have an elongated form (6), a pair of tentacles, and four legs, 

 with which they swim freely in the water. 



555. Their freedom, however, is of but short duration. 

 The little animal soon attaches itself by means of its tentacles, 

 having previously become covered with a transparent shell, 

 through which the outlines of the body, and also a very distinct 

 eye, are easily distinguished (c). Fig. 370, d t shows the 

 animal taken out of its shell. It is plainly seen that the 

 anterior portion has become considerably enlarged ; subse- 

 quently, the shell becomes completed, and the animal casts its 



A A 2 



