Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett.
- Karl Theodor Ernst von Siebold
- Date:
- 1854
Licence: Public Domain Mark
Credit: Comparative anatomy / by C.Th. v. Siebold and H. Stannius ; translated from the German, and edited with notes and additions recording the recent progress of the science by Waldo I. Burnett. Source: Wellcome Collection.
Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.
57/482 (page 53)
![§ 47. I. With those polyps which are not sexless, and whose alimentary canal hangs free in the cavity of the body, the sexual organs are situated in this last. They often escape attention, since they are scarcely at all developed except at the sexual epoch. Both ovaries and testicles frequently appear as riband-like bodies, which, being attached by one extremity alone to the stomach, move freely in the general cavity of the body. Sometimes, however, they are attached longitudinally by one of their borders, like a mesentery, the opposite border being free. In other cases, again, they are attached directly to the sides of the body. The eggs and spermatic particles pass directly from the sexual organs into the cavity of the body. In Coralla having individuals of both sexes, fecundation takes place in the cavities of their bodies, which connect with each other.® With the others, however, the individuals of which are of one sex alone, the surrounding water is the medium of fecundation, by transporting the spermatic particles unaffected to the eggs; and this being performed by the aqueous circulation before mentioned, impregnation takes place in the cavity of the body. § 48.* The variations of the internal genital organs in the different families are as follows: 1. With the Bryozoa, a riband-like ovary and testicle are suspended from the extremity of the stomach. In these organs are developed only two to four eggs or fasciculi of spermatic particles, from cells arranged like a string of pearls.® The eggs, of which the germinative vesicle and dot disappear at a very early period, are detached from the ovary before their shell is well formed,, and are set in motion by the cilia of the cavity of the body. Usually they are flattened, and at first enveloped by a thin and colorless membrane, which soon becomes thicker and darker, and has upon its borders a clear, 1 With Tendra zostericola, which is allied to Flustra, the Polyps are contained in cells closely bound to each other. But the cells of the males communicate with those of the females by an open- ing, through which the spermatic particles pass into the cavity of the body of the female (see Nordmann, Ann. d. Sc. Nat. XI. 1839, p. 191). and the particles themselves are the metamor- phosed nuclei of these cells, exactly as in other and higher animals. They have invariably, as far as I am acquainted, a cercaria-form consisting of a solid head, to which is attached a most delicate tail. The shape of this head, when studied carefully with the best powers, presents differences of zoological import. Sometimes it is pyriform (Tubularia, Actinia), sometimes conical (Astrangia), while among the Bryozoa it is long-oblong with Alcyo- nclla. I cannot therefore agree with Kdlliker (Cyclop. Anat. Art. Semen. 1849, p. 497) as to the mode of development of these particles with these animals. — Ed. 1 See. for Alcyonella stagnorum, Meycn (Isis, 1828, Taf. XIV. fig. 1), for Plumatella cristata, IJumortier (loc. cit. pi. I. fig. 3, u, u) and for Cellaria avicularia, Nordmann (Obs. sur la Faune Pontique, p. 679, fig. 4, A. n).f * [§ 48.] In an emendatory note at the end of the volume, the author remarks: “Sections 21 and 3d of this paragraph should be omitted, since the genital organs, with all the Anthozoa, are attached on the internal surface of the visceral cavity. See Frey and Lcuckart. Beitr. &c. p. 13.” I have, however, allowed them to remain, for the sake of their notes. — Ed. t [ § 48, note 1.] My own researches in 1851 have shown me that with Alcyonella the sexes are separate. The testicles and ovaries consist of pedun- culated sacs, closed at first, but which are rup- tured on the mature development of their contents. — Ed. 5*](https://iiif.wellcomecollection.org/image/b2491874x_0057.jp2/full/800%2C/0/default.jpg)
