This section is from the book "General Outline Of The Organization Of The Animal Kingdom, And Manual Of Comparative Anatomy", by Thomas Rymer Jones. Also available from Amazon: A General Outline of the Animal Kingdom and Manual of Comparative Anatomy.
* Descriptive and Illustrated Catalogue of the Physical Series of Comparative Anatomy in the Museum of the Royal College of Surgeons of England, vol. i. p. 259.
(1176). In opposition to the views entertained by Cuvier concerning the generative process in the class before us, various continental writers consider the true ovary to be contained in the cavity of the tubular fleshy pedicle, which in Pentelasmis serves to fix the body to the substance whereunto it is attached. This, indeed, at certain periods, is found to be filled with oval granular bodies of regular shape, which are apparently real ova, diffused through the loose cellulosity enclosed within it; and these ova, being found in different states of maturity, are apparently secreted in the pedicle itself, - although some authors contend that, having been formed and impregnated in the manner indicated by Cuvier, they are conveyed into this situation by the ovipositor, as upon this assumption the prolonged organ (fig. 235, k) would be named. Other anatomists, again, regard the instrument last mentioned as being a real penis, and suggest that from its length it might even be introduced into the peduncular cavity itself, and thus effect the impregnation of the ova contained therein.
(1177). It is to Mr. Darwin that science is indebted for a knowledge of the fact that in at least two genera of the Lepadidae distinct male and female individuals exist; and for the far more wonderful discovery that in the same genera there exist hermaphrodite species, whose masculine efficiency is aided by one or two complemented males. In the genus Ibla for example, in one species, I. Cumingii, the egg-bearing individual is simply female, presenting no trace either of the external proboscidi-form penis, or of the vesiculae seminales, or of the testes; while, on the other hand, the ovarian tubes within the pedicle are developed in the usual manner, as are likewise the true ovaria at the upper edge of the stomach. But although there thus was a total deficiency of the usual male portion of the sexual apparatus, Mr. Darwin found attached within the sac, in a nearly central line (fig. 236,h), a flattened, purplish, wormlike little animal, which, notwithstanding its different appearance, turned out upon dissection to be, in reality, the male Cirriped belonging to this species, although totally dissimilar in its external configuration.
(1178). The dimensions and proportions of the male animal vary much; but it is always exceedingly minute, the longest specimen measuring not more than 8/100ths of an inch in length. The main part of the body consists of the peduncle, which tapers more or less suddenly towards its extremity, which latter is imbedded deeply in the integuments of the female, passing obliquely through the chitine-membrane and corium, and, running along amidst the underlying muscles and inosculating fibrous tissue, is attached to them by cement at the extremity.
(1179). Within the muscular layer all round the upper part of the peduncle, and surrounding the stomach, the body of this minute creature contains numerous little, rather irregular, globular balls with brown granular centres, so closely resembling the testes in other Cirri-pedes as to leave little doubt that they are of the same nature. The vasa deferentia are plainly visible, occupying their normal situation; and the presence of spermatozoa is indisputable. The vasa deferentia unite and terminate under the two extremely minute caudal appendages: but there is no projecting proboscidiform penis; and in this case apparently the whole body, furnished like the penis with longitudinal and transverse muscles, serves the same purpose!
(1180). Another species belonging to the same genus, Ibla quadri-valvis, furnishes an example of a hermaphrodite Cirriped, which might be supposed to be in itself sufficient for reproduction, provided with a complemental male, - an arrangement still more wonderful than that just described as existing in I. Cumingii. In the androgynous individual there is a penis, singularly constructed of several distinct segments, as well as the vasa deferentia and testes, which latter are unusually large and egg-shaped, while the ovigerous system is likewise completely developed j nevertheless in five out of six specimens dissected by Mr. Darwin males were present, in every respect similar in their structure to those of I. Cumingii described above, and of some of which he was enabled to trace the preparatory metamorphoses, common to the class, from their larval condition to the adult state.
(1181). In this same hermaphrodite specimen of Ibla quadrivalvis, the two ovigerous lamellae contained some hundreds of larvae in the first stage of development, which were liberated from their enveloping membranes by a touch of a needle; they were about 16/1000ths of an inch in length, and presented all the usual characters of larvae at this period. What a truly wonderful assemblage of beings of the same species, exclaims the distinguished naturalist to whom we are indebted for these researches, did this individual hermaphrodite present! We have the numerous, almost globular larvae, with lateral horns to their carapaces, with their three pairs of legs, single eye, proboscidiform mouth, and long tail: we have the somewhat larger lame, 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.