§$ 47, 48. THE POLYPI. 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 situ.ated 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 1 See, for Alcyonella stag-norum, Meyen (Isis, 



Flustra, the Polyps are contained lq cells closely 1828, Taf. XIV. fig. 1), for Plumate/la cristata, 



bound to each other. But the cells of the males Dumortier (loc. cit. pi. I. fig. 3, u, u) and for 



communicate with those of the females by an open- Cellaria avicularia, Nordmann (Obs. gur la 



ing, through which the spermatic particles pass Tauue Pontique, p. 679, fig. 4, A. n).t 

 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- *[§ 48.] In an emendatory note at the end of 



phosed nuclei of these cells, exactly as in other and the volume, the author remarks: " Sections 2d and 



higher animals. They have invariably, as far as I 3d of this paragraph should be omitted, since the 



am acquainted, a cercaria-form consisting of a solid genital organs, with all the Anthozoa, are attached 



head, to which is attached a most deUcate tail, on the internal surface of the visceral cavity. See 



The shape of this head, when studied carefully with Frey and Leuckart. Beitr. &c. p. 13." I have, 



the best powers, presents differences of zoological however, allowed them to remam, for the sake of 



import. Sometimes it is pyriform {Tubularia, their notes. — Ed. 



Actinia), sometimes conical (Astrangia), while t[§48, note 1.] My own researches in 1851 



among the Bryozoa it is long-oblong with Alcyo- have shown me that with ^/cifoMe^/a the sexes are 



nella. I cannot therefore agree with Kblliker separate. The testicles and ovaries consist of pedun- 



(Cyclop. Anat. Art. Semen. 1849, p. 497) as to the culated sacs, closed at first, but which are rup- 



mode of development of these particles with these tured on the mature development of their contents, 



animals. — Ed. — Ed. 



5* 



