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.
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![The Campanulariae and Sertvlariae produce at the end of their pedicle and branches elongated sexless individuals. But in the angles of these branches cells of another form, and containing many sphei’ical individuals, are developed. In these last sexual organs are formed, which, in Campan- ularia geniculata, occurs without a separation of the new individuals from the corallum, while in Campanularia gelatinosa it is after detachment has taken place.® § 46. In the eggs of polyps both a germinative vesicle and dot may often be seen. Frequently, however, both disappear at a very early period. The envelopes of the egg are usually of a simple/1’ though sometimes of a complicated structure. The spermatic particles are very active, and in some species are filamentoid, in others composed of a solid body or head, to which is appended a very delicate tail. Water does not appear to affect either their form or motion.® 5 According to Krohn (Muller's Arch. 1843, p. 174), it is probable that in Campanularia and Ser- tularia both sexes are developed in this way. From Ellis’ description of Campanularia dicho- toma (Essai sur PHisfc. Nat. des Corallines, p. 116, pi. XXXVIII. fig. 3), it may be concluded that the females, mistaken by these naturalists for eggs, separate in this way from the corallum. Me yen (Nov. Act. physico-medica. XVI. Suppl. I. 1834, p. 195, Tab. XXX. fig. 3, 4) has also taken the medusoid females of this species for spawn. [Additional note to § 45.] The series of those polyps, the sexless (nurse-like) individuals of which produce self-dependent, medusa-like young, has been increased by several more recent re- searches. See Van Reneden, Rech. sur l’embryol. d. Tubulaires, 1844, pi. I. IV. (Tubularia and Eudendrium) •, Sars, Faun, littoral. Norveg. p. 7, Tab. I. (Podocoryna and Perigonimus) ; Du- jardin, Ann. d. Sc. Nat. IV 1845, p. 257, pi. XIV. XV. (various Ilydrina). It is true .that the de- velopment of the genital organs has not been ob- served in these medusa-like individuals 5 but they have indeed in the medusiform individuals of Syn- coryne ramosa and Coryne fritillaria, and there- fore it may be proper to infer that the same is true of other Hydrina and Sertularina. If it is cor- rect to regard as the perfect state that in which the individuals resemble Meduste, and as the im- perfect state that in which they are polypoid, then should we, as has been done already by many, re- move these animals from the class of the Polypi, and place them with the Acalephae.* 1 In most Anthozoa. Eggs of this kind, belong- ing to Actinia, Coryne and Veretillum, have been figured by Wagner (Wiegmann's Arch. 1835,1. Taf. III. fig. 2 ; Prod. Ilist. Gener. hom. atque anim. Tab. I. fig. 1, and leones zoot. Tab. XXXIV. fig. 5,17, 23). 2 With most Bryozoa the spermatic particles are filamentous. Both from their size and their * [ End of additional note to § 45.] The remark- able relations here spoken of, and the conjectures as to the real zoological nature of the animals in question, have been pretty satisfactorily cleared up by the recent researches of Agassiz. He has shown that the Hydroid Polyps are not simply a lower form of stemmed animals, producing at a given period more highly-organized Medusae, but that they are themselves, by their structure, real Medu- motions, they have been taken for parasites. Kblliker (Beitr. zur Kennt. d. Geschlechtsverhalt. u. d. Saamen. Fliissigkeit wirbellos. Thiere, p. 41, Taf. II. fig. 17) has seen the spermatic particles of a thread-like form, of Flustra carnosa, develop- ing in cells, and has seen them moving in the cav- ity of the body. I have seen similar ones in Crista- tella mirabilis and Plumatella campanulata. Those which were seen by Farre (Phil. Trans. 1837, p. 403, pi. XXIII. fig. 5, g) in the cavity of the body of Valckeria cuscuta, and were re- garded by him as intestinal worms, have an oval body, to which is attached a delicate tail. Nord- mann (Faune Pontique loc. cit.) has found those of Cellaria avicularia having the same form. Those of Actinia have also a similar form (see Erdl Muller's Arch. 1842, p. 301, and Kblliker, loc. cit. p. 44, fig. 13). One should be careful and not confound the spermatic particles with the nettling organs having a similar form 5 and especially as the development of these last has apparently some connection with that of the sexual organs (see Erdl loc. cit. p. 305). According to Kblliker, the spermatic particles of Alcyonidium gelatinosum have a lanceolate body, with a hair-like tail (loc. cit. fig. 10J. Spermatic particles of a cercaria-form have been observed by Wagner (Icon. zoot. Tab. XXXIV. fig. 7, 12) with Veretillum and Hydra; by Van Beneden (Rech. sur l’organisat. d. Laguncula, and Rech. sur l’anat. d. Bryozoaires, pi. V. in the Nouv. M£m. de Bruxelles, &c. XVIII.), with La- guncula and Ha/odactylus; by Rathki (Wieg7 mann's Arch. 1844, I. p. 161, Taf. V. fig. 6) and Steenstrup (Untersuch. iib. das Vorkommen d. Hermaphrodit. p. 66, Taf. I. fig. 18, e) with Coryne ; finally by Kblliker (Nene Denkschr. VIII. p. 48, fig. 20, 21, 22, 24) with Pennaria, Eudendrium and Sertularia. In Crisia, on the other hand, Kblliker found the spermatic particles perfectly filiform, f sae. See Lectures on Comparative Embryology, 18485 also Proceed. Amer. Assoc, for the Advance- ment Sc. 1849 (“ On the Plan of Structure and Ho- mologies of Radiated Animals”), and Mem. Amer. Acad. loc. cit. p. 225. — Ed. t [ § 46, note 2.] I have been able to trace the development and character of the spermatic par- ticles of many of the true Polyps and the Bryozoa. The development occurs in special daughter-cells,](https://iiif.wellcomecollection.org/image/b2491874x_0056.jp2/full/800%2C/0/default.jpg)
