458 CIKKHOPODA. 



in the last stage of their development, much compressed, boat-formed, 

 with their two great compound eyes, curious prehensile antennae, closed 

 rudimentary mouth, and six natatory legs, so different from those of 

 the first stage : we have the attached males, with their bodies reduced 

 almost to a mouth, placed on the summit of a peduncle, with a minute, 

 apparently single eye shining through the integuments, without any 

 carapax or capitulum, and with the thorax, as well as the legs or cirri, 

 rudimentary and functionless : lastly, we have the hermaphrodite 

 with all its complicated organization, its thorax supporting six pairs of 

 multi-articulated two-armed cirri, and its well- developed capitulum, 

 furnished with horny valves, surrounding this wonderful assemblage of 

 beings. Unquestionably, without a rigid examination, these four forms 

 would have been ranked in different families, if not orders, of the Arti- 

 culated kingdom. 



(1182.) The observations of Mr. Thompson* relative to the progress 

 of the ova after their escape from the pedicle throw much additional 

 light upon this portion of our subject. " In the whole tribe of Cirripeds," 

 says this industrious naturalist, "the ova, after their expulsion from 

 the ovarium, appear to be conveyed "by the ovipositor into the cellular 

 texture of the pedicle, just beneath the body of the animal, which they 

 fill to the distance of about an inch. When first placed in this position, 

 they seem to be amorphous, and inseparable from the pulpy substance 

 in which they are imbedded ; but as they approach to maturity they 

 become of an oval shape, pointed at both ends, and are easily detached. 

 Sir Everard Home has given a very good representation of them at this 

 stage of their progress, in his ' Lectures on Comparative Anatomy/ from 

 the elegant pencil of Mr. Bauer. 



(1183.) " During the stay of the ova in the pedicle, they render this 

 part more opake and of a bluish tint, the ova themselves, and the 

 cellular texture in which they are surrounded, being of a pale or azure - 

 blue colour. It is difficult to conceive in what manner the ova are ex- 

 tricated from the situation above indicated ; but it is certainly not by 

 the means suggested by Sir E. Home in the above-mentioned lecture, 

 viz. by piercing outwards through the membranes of the pedicle ; for 

 the ova are subsequently found forming a pair of leaf-like expansions, 

 placed between either side of the body of the animal and the lining 

 membrane of the shells. These leaves have each a separate attachment 

 at the sides of the animal to the septum which divides the cavity occu- 

 pied by the animal from that of the pedicle : they are at first compa- 

 ratively small, having a rounded outline, and possess the same bluish 

 colour which the ova had in the pedicle ; but as the ova advance in 

 progress, these leaves extend in every dimension, and lap over each 

 other on the back, passing through various lighter shades of colour 

 into pale pink, and finally, when ready to hatch, become nearly white. 

 * Phil. Trans, for 1835, p. 356. 



