^ 69. THE ACALEPHAE. 71 



§69. 



The position of the sexual organs varies in the different orders, in the 

 following manner : 



1. With the Ctenophora, which are hermaphrodites, they arc situated 

 along the sides, under the form of elongated utricles, the testicles being 

 on one side and the ovaries on the other. They have a nodulated appear- 

 ance, and from the lower part of each passes off an excretory duct, which 

 runs toward the mouth, but the terminal opening of which has not yet been 

 well made out.''' 



2. With many Discophora, these organs are arranged like rays, passing 

 from the centre to the border of the disc. In Oceania, Cytaeis, Geryonia 

 and Thauma7itias, the four saccular ovaries or testicles form at the centre 

 of the disc a cross, which is traversed by four aquiferous canals.*^' Their 

 excretory ducts pass towards the base of the stomach, but their terminal 

 openings are not distinct.'^' In the disc of Aequorea violacea, seventy -four 

 ray-like bands are spread out, and the free plicated borders of these hang 

 beneath the inferior surface of the disc, thus permitting the free escape of 

 the eggs and sperm into the water.''*' 



3. Another group of the Discophora have at the base of their tentacles 

 four large openings, which lead into as many cavities in the disc.'^ At the 

 base of these cavities, which formerly were regarded as respiratory organs, 

 the genital organs are situated in the form of plicated bands. These as four 

 bands (testicles or ovaries) are bent either into an angle or the arc of a cir- 

 cle, forming sometimes a star with four rays,''"' and sometimes a four-lobed 

 rosette. '"^^ If these cavities increase in number, the genital organs increase 

 in the same proportion.'^' The border of these organs is generally pro- 

 vided with numerous tentacles which project into the cavity.''-" In the riband- 

 like testicles numerous small sacs are observed ; each one of these opens 

 separately into the genital cavity, while the eggs, on the contrary, are sep- 

 arated from the similarly-formed ovary only by a gradual constriction of 

 the latter.'"" 



4. With the jiphonophora, all the relations of these genital organs still 

 require much investigation. With the Diphyidae, they consist of sacs 

 oommunicat' g with the general cavity of the body.'"' During the epoch 



1 Will, Horae tergest. p. 38, Taf. I. fig. 22, 23. cit. Taf. VII. ; and Wagner, Icon. zoot. Tab. 



2 Wagner, Icones. zoot. Tab. XXXIU. fig. 26, XXXIII. fig. 13. 



a. a. ; Will, loc. cit. Taf. II. fig. 5, 7, 8, 14, 16 ; W Siebold, Beitrage loc. cit. Taf. I. fig. 20, 23 ; 



BtoinuiV/e, Manuel d'Actiuol. 182^. " ""^'XVTT. and A'o//i^er, Beitrage loc. cit. p. 40. 



fig. 3 ; and Sars, Beskrivelser loc. cit. iri. < . i.^. U In Diphyes and Ersaea, a sac filled with cells 



12, 13. opens into the general cavity of the body, and 



3 Will, loc. cit. p. Yl. communicates beside with the stomachs and respi- 

 i Milne Edwards, Ann. d. Sc. Nat. XVI. p. 198, ratory cavities. Will (Horae tergest. p. 78, 81, 



PI. I. fig. 1, a. b. Taf. II. fig. 23, c.) regards tliis sac as a sexual 



5 Gaede, Beitrage loc. cit. Taf. I. fig. 1, c. (Me- organ ; and Meyen (Nov. Act. physico-med. XVI. 

 dusa) ; and Lesson in Duperrey, Voyage loc. cit. Suppl. 1, 1834, j). 214, Tab. XXXA'I. fig. 2, h. and 

 No. 12, 13 (Chrysaora). fig. 6, 7) asserts to have seen eggs in it. Accord- 



6 Rkizostomum. ing to Pkilippi (Muller's Arch. 1843, p. 63, Taf. 



7 Chrysaora, Medusa, Pelagia and Aurelia. V. fig. 10, a. b.), the- grape-like clustered genital 

 See Elirenberg-, Abhaudl. d. Berl. Akad. 1835, organs, with PA^so/>/iora, are situated between the 

 Taf. I. fig. 1 : Wagner, Icon. zoot. Tab. XXXIII. prehensile organs ; the smallest containing in each 

 fig. 1 ; and Brandt, M^ra. de I'Acad. de St. Peters- lobule six to ten eggs, and the largest a granular 

 burg, IV. PI. IX. X. With the male and the female liquid (Sperm ?). 



Ce;)Aea, I have found the testicles and the ovaries i/o//ard (Ann. d. Sc. Nat. III. I"'""' " "'" PI. 



disposed exactly as with the " . ' ' IV. bis. fig. 33, 34) has found buUj . . . -b (if 



8 In Ca«.S2ope«(, the.se organs ai,. ^i^nL in iiu.nber. ovariss .-^i ''. ' i'" "<" the tubuliform tentacles 



9 Medusa and Pelagia; see Ehrenber^, loc. (stomachb;. ........ ^. ^ ii p. 37, PI. V.) has also 



