1105 



CIRRIPEDIA. 



CIRRIPEDIA. 



1106 



be described, to a fold of skin on each side of the sac ; these two 

 folds Darwin calls the Origerous Fraena. As the lamellae are formed 

 without organic union with the parent they would be liable to be 

 washed out of the widely-opened sac of the Lepadidce if they had 

 not been specially attached to the fraena. 



The complemental males, to which we have before alluded, occur 

 in the genera Ibla, ScalpMum, A loippe, and Cryptophialtis ; and these 

 males are permanently attached to the females. In Ibla the male is 

 attached within the sac of the female ; it has a well-organised mouth 

 supported on a peduncle, but with only a rudiment of the thorax, and 

 with only two pairs of aborted cirri. In Scalpellum the males differ 

 in the different species remarkably in structure : in some of the 

 species they are not very unlike ordinary Pedunculated Cirripedes, 

 and are attached between the scuta of the females ; in other species 

 the males are very rudimental, extremely minute, and would never 

 without close examination have been thought to have even belonged 

 to the class Cirripedia. These males consist of a sac, with rudiments of 

 four valves, inclosing a singularly modified thorax, with only four pairs 

 of appendages (which cannot be called cirri) ; they are entirely destitute 

 of a mouth or stomach. The males of Cryptophialus and A Icippe are 

 even more rudimentary than those of the above species of Scalpeltum : 

 they are reduced to an outer envelope (homologous with the carapace 

 of ordinary Crustacea), to a single eye, the testis, vesicula seminalis, 

 and a wonderfully elongated proboscifonned male organ'. Hence 

 there is no mouth, no stomach, no thorax, no abdomen, and no 

 appendages or cirri. It may be doubted whether in the whole animal 

 kingdom there exists a [creature in a more rudimentary condition 

 than these males. As they do not possess a mouth or stomach they 

 are necessarily short-lived. The pupa fixes itself on the female, 

 becomes cemented to her, undergoes its metamorphosis, and becomes 

 a male Cirripede; the spermatozoa become developed and are 

 discharged ; the male dies, decays, and generally drops off, and is 

 succeeded, when the ova in the female are next ready to be 

 impregnated, by one or more fresh males. Owing apparently to the 

 Bin.ill size of the males, there is generally more than one attached to 

 the female at the same time ; and in the case of Alcippe lampat 

 Mr. Darwin found no less than thirteen of these singular parasitic 

 and rudimentary males attached to a single female ! 



Remarkable as is the occurrence of the above male parasites on the 

 females, it is a far more singular fact, that in some of the species of 

 Ibla and Scalpettum, the males are attached, not on females, but on 

 hermaphrodites ; and hence they have been called by Mr. Darwin 

 Complemental -Males, inasmuch as they are complementary to the 

 male organs of the hermaphrodite. Mr. Darwin, in his work on 

 the Cirripedia (p. 281), published by the Ray Society, enters at 

 length on the evidence in support of this view, and he believes the 

 facts cannot be controverted, (p. 214.) " Although the existence of 

 hermaphrodites and males within the limits of the same species is a 

 new fact amongst animals, it is far from rare in the vegetable king- 

 dom : in such cases the male flowers are sometimes in a rudimentary 

 condition compared to the hermaphrodite flowers, exactly in the same 

 manner as are the males of Ilila and Scalpelltan. If the final cause of 

 the existence of these Complemental Males be asked, no certain answer 

 can be given ; the vesiculse seminales in the hermaphrodite of Ibla 

 quadrivalvit, and in some species of Scalpelhtm, appeared to be of 

 small diameter ; but on the other hand the ova to be impregnated 

 are fewer than in most Cirripedes. No explanation can be given of 

 th<> much simpler case of the mere separation of the sexes in the 

 four genera before enumerated ; nor can any explanation be given of 

 the much more varied arrangement of the parts of fructification in 

 plaitts of the Linnean class Polygamia." 



The following woodcuts will give an idea of *he structures above 

 described, more especially in accordance with the views of Martin- 

 Saint-Ange : 



Fif/. 1 . A natife jaune sans coquille (Cuvier, A lepas ? ) : A, a gelatinous 

 production, the cement, which serves to fix the peduncle ; B, the 

 first membrane of the peduncle ; B' a small Cirripede, of the natural 

 ize developed upon the peduncle of the parent ; C, the capitulum, 

 which contains the body of the animal ; D, the fissure of the capitu- 

 lum from which issue the feet or cirri F. The point E indicates the 

 termination of the peduncle, and the place where the eggs stop ; G, 

 the eggs arrived within the sac. Fig. 2. The same letters refer to 

 the same partsas in fig. 1 ; H, the pedicles of the cirri, which sustain 

 the rami, F. At the base of the feet (H) are four branchiae ; and 

 between these feet and those placed on the other side is seen the 

 recurved tube which serves to convey the seminal liquor to the 

 ' ova within the sac. Fig. 3. The same Cirripede, from which thg 

 half of the first envelope has been taken so as to expose the interior. 

 The peduncle contains a second cylinder terminated in a cul-de-sac 

 by its inferior extremity, and covered at the other by a very deli- 

 cate membrane ; the longitudinal and transverse muscular fibres may 

 be observed ; , e, indicate the canal which, according to Saint-Ange, 

 carries the eggs of the peduncle within the sac ; ft, that which serves 

 as a nourishing vessel to the peduncle and the eggs ; y, g, the mem- 

 brane of the sac which intercepts all direct communication between 

 the peduncle and the cavity of the sac. J represents the body of 

 the Cirripede inclosed in its proper envelope, fig. 4. The same situa- 

 tion as the last, representing all the membranes which envelop the 



BAT. HIST. DIV. VOL. t. 



