Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement.
- Johannes Peter Müller
- Date:
- 1848
Licence: Public Domain Mark
Credit: Embryology, with the physiology of generation ... / Translated from the German, with notes, by William Baly ... From Müller's Elements of physiology and supplement. Source: Wellcome Collection.
54/376 page 1454
![In many of the Infusoria Ehrenberg lias discovered the male and female organs. The Polypi are likewise for the most part hermaphrodite. Amongst the Campanulariae, however, they are, according to the ob¬ servations of Ehrenberg and Lowen, distinct male and female indivi¬ duals. Many polypes of the stock were observed by them to have all the organisation necessary for individual life, whilst in others the arms and internal organs essential to individual life, were atrophied, and these appeared to be converted into ovaries. These metamorphosed polypes had, indeed, been previously described as ovaries by Cavolini and others.* Nordmann has published similar observations respecting his Tendra zostericola, in which the male and female cells are situated close to each other. The testes of the male polype consist of eight vermiform organs placed near the tentacles. The ova of the female cells are fecundated by the spermatic animalcules of the male polypes. + In other polypi, as the Actiniae, both ovaries and testes are known. R. Wagner J has discovered seminal animalcules in convoluted tubes of the Actiniae. Similar tubes have been seen by Edwards § in compound Polypifera; but it is not known whether they contain seminal animal¬ cules. || Amongst the Acalephae the Medusae, at least, appear from the recent researches of Siebold to possess separate sexes. The males of the Medusa aurit.a are smaller than the females,'—have not the small sacs in the tentacles, and never contain ova. In the testes of the male Medusa, Siebold has detected spermatozoa. The class Entozoa includes genera devoid of sexes, hermaphrodites and genera with the sexes in distinct individuals. The Ccenurus and Echinococcus among the Taenioidea cystica (the Cystica of Rudolphi) seem to propagate wholly by the development of buds. The Taeni¬ oidea cestoidea (the Cestoidea of Rudolphi) are hermaphrodite, and afford instances both of self-impregnation and of reciprocal impreg¬ nation. In the animals of this order the generative organs and their external openings are repeated in all the fully developed segments, lentin (in the Holothuria and Spatangus), Wagner (also in the Holothuria), Rathke (in the Asterias and Ophiura), and by Petei’s (in the Echinxxs). See Valentin in Fro- riep’s Notizen, bd. xii. No. 7, and Repertor, 1840, p. 301. Rathke, Froriep’s Not. b. xxi. No. 260, and No. 331. Peters, Muller’s Archiv. 1840, p. 144.] * See Lowen, in Wiegmann’s Archiv. iii. p. 249. -f Ann. des Sc. Nat. xi. p. 185. J Wiegmann’s Archiv. i. No. 5, 213. § Ann. des Sc. Nat. 1835, December. || [Edwards has since detected Spermatozoa in these tribes of the Polypifera (Ann. des Sc. Nat. 1840). Van Beneden describes distinct males and females in Alcyonella (Ibid.), and Exall lias observed that part of Veretillum is male and part female (Fro- riep’s Notiz. 1840, No. 240). See also Wagner’s observations on the separate sexes of the polype, Veretillum, Froriep’s Notiz. xii. No. 7- Dr. A. Farre observed a number of animalcules, like Cercariae, in the visceral cavity of Sertulariae. Phil. Trans. 1837, Pt. ii.] f[ See Midler’s Archiv. 1837, p. 438.](https://iiif.wellcomecollection.org/image/b29339601_0054.jp2/full/800%2C/0/default.jpg)
