38 NATURAL ARRANGEMENT OF INSECTS. 



by the valves of the shell, are pedunculated, as in the 

 crab and lobster, and placed anteriorly at the sides of 

 the body. Any naturalist acquainted with the Crustacea, 

 on reading this short description, will readily assent to 

 what has been advanced as to the very extraordinary 

 and anomalous character of this little animal, and to 

 the dislocations it seems calculated to produce in our 

 classifications. But for its pair of pedunculated eyes, 

 it would find place as a new genus of the bivalve Mo- 

 noculi i^Ostracoda) ; its members approximate it to Ar- 

 guliis on the one hand, and to Cyclops on the other, — 

 genera which are widely separated ; while its eyes show 

 its relation to the crabs, lobsters, and other decapodous 

 Crustncea. Reflecting upon these circumstances, on 

 their great abundance during the early part of spring 

 alone, and their presenting no variation indicative of a 

 difference of sex, induced a belief that they were the 

 larvae of some crustaceous animal." With these impres- 

 sions, our author procured some more of these creatures 

 in the spring of 1 826 ; " and in order to see what changes 

 they might undergo, they were kept in a glass vessel, 

 covered by such a depth of sea water, that they could be 

 examined at any time by means of a common magnifying 

 glass. They were taken I\Iay 1st; and on the night of the 

 8th, the author had the satisfaction to find that two of 

 them had thrown ofi" their exuvia, and, wonderful to say, 

 were firmly adhering to the bottom of the vessel, — 

 changed into young barnacles ! such as are usually seen, 

 of Balanus pusillus Pen., intermixed with grown spe- 

 cimens on rocks and stones at this season. In this stage, 

 the sutures between the valves of the shell and of 

 the operculum were visible, and the movements of the 

 arms of the animal within, — although these last were not 

 yet completely developed : the eyes, also, were still per- 

 • ceptible, although the principal part of the black colour- 

 ing matter appeared to have been thrown off" with the 

 exuvium. On the tenth day, another individual was seen 

 in the very act of throwing off its shell, and attaching 

 itself, like the others, to the bottom of the glass. It 



