Invertebrata. Zoological Collections. \V5 



4. On the Cirripedes or Barnacles; demonstrating their deceptive cha- 

 racter ; the extraordinary metamorphosis they undergo, and the class of 

 animals to which they indisputably belong. 



— Addendum on Nehalia. 



In extracting this latter article, it must not be supposed that we wish to 

 give a specimen of the work ; for the avowed object of the author was 

 merely to report what has been already communicated, as to the structure 

 and habits of these anomalous and little known Crustacea, in the hope of 

 attracting naturalists to the examination of so interesting a genus. We shall 

 recur to the author's discoveries Ed.] 



The best informed naturalists have associated Nobalia with the Shizopodae, 

 from the circumstance of having their members cleft or divided into two 

 branches, and their appearing to have a pair of pedunculated eyes ; when, 

 however, we are aware of all the anomalies which affect the limbs and visual 

 organs in the Crustacea, we shall not be apt to attach much importance to 

 characters derived from parts liable to such extraordinary deviations, when 

 •they are not at the same time accompanied by some approximation in the 

 general form and stmcture to the rest of the animals of the group ; this is 

 by no means the case with Nebalia, which in every other respect is an animal 

 sui generis, but certainly bears a greater degree of affinity to the larvae of the 

 Balani than to any other. Its antennae, no doubt, constitute one difference, 

 while its eyes and tail are exserted beyond the boundary of the corslet, — 

 differences which we might be prepared to expect in the larvae of the various 

 genera of the Balani. Indeed, since the discovery announced in the pre- 

 ceding memoir,* it is difficult to dismiss a suspicion that Nebalia may be th6 

 larva of some one of those types; and, in particular, of Coronula ; the 

 larvte of this genus must of necessity possess useful eyes, and a more 

 powerful and perfect natatoiy apparatus, in order to perceive and pursue the 

 cetaceous animals (whales) upon which they finally fix themselves. 



We must not, however, shiit our eyes to the facts furnished by Otho 

 Fabricius, in regard to the breeding of Nebalia, which, if not deceptive, com- 

 pletely annul any such idea, and shew it to be a peculiar genus, most nearly 

 related to the larvae of the Balani, to which it will thence bear the same 

 relation as Mysis to the Decapodous Macroura. 



The first animal of the present type was discovered by Otho Fabriciu^, 

 and published with a figure in his Fauna Groelandica, under the title of 

 Cancer bipes, p. 256, No. 223, f. 2, which figure has been copied by Herbst 

 inhis workon Crabs, &c. PI. XXIV. f. 7. Montagu more lately detected, 

 on the south coast of Devon, the individual figured in the Linnaean Transac- 

 tions, vol. XI. t. 2, f. 5 ; and, still more recently, Dr Leach, the founder 

 of this genus, has furnished us with a third, to which he assigns as a habita- 

 tion, the European Ocean Zool Misc. vol. I, p. 100, t. 44. 



All these, Dr Leach, Desmarets, and some other naturalists, consider as 

 identical, or of the same species ; and, as the former gentleman, from his 

 more intimate knowledge of the accuracy and discriminating powers of his 

 friend Montagu, is of this opinion, it would be presumptuous in us to dis- 

 pute the propriety of this decision. Mons. Lamarck, not svi'ayed by this 

 consideration, very properly considers the Nebalia of Fabricius and Leach 

 different from that of Montagu. The differences, however, are principally 

 such as might be supposed to arise from the latter using magnifiers of higher 

 power, and bringing to the examination a greater or less degree of skill and 

 scientific knowledge : thus his figure has all its members and tail fringed 

 with hairs, and the styles of the tail annulate. 



To observe animals of this small size and concealed character by simple in- 

 spection, will not exactly answer the purposes of natural science as at presertt 



* On the metamorphosis of the Cirripedes, or barnacles. 



