54 THE POLYPI. <§>§ 49, 50. 



transparent ring. In Alcyonella and Plumatella, the eggs are of an oval 

 shape, and of a dark-brown color. In Cristatella mirabilis, T)al.. {Crista- 

 tclla miccedo, Cue), they are lenticular and clear brown, and have this re- 

 markable peculiarity : ^-* Upon both sides of the encompassing ring are a 

 number of double-pointed hooks, which, at first, are imbedded in a gela- 

 tinous substance ; but as this last is dissolved by water, they become free, 

 and adhere to plants and other bodies.'''* 



2. With many Anthozoa, having a cavity of the body, the sexual or- 

 gans are attached in the form of bands along the external face of the 

 stomach. These are numerous, and during the epoch of reproduction their 

 free bordei's are often plicated, and have a botryoidal aspect. This form 

 is quite apparent in the Actiniae, where these organs are contained in sep- 

 arate chambers of the cavity of the body.'^' The same is true of the Ed- 

 wards', ae.^''' With Verelilhan <"* and Alcyoidnm '-''' these organs ibrm mesen- 

 teric divisions which descend deep into the cavity of the body, 



3. In Alcyonidium elegans *"'■ and Tubipora musica *'" these organs are 

 attached to the internal surface of the cavity of the body, and have a pli- 

 cated mesenteric form.''"* 



§49. 



The laying of the eggs takes place in different ways with those Polyps 

 having internal sexual organs. With the Bryozoa it probably occurs 

 through the openings near the anus.*'' With the Anthozoa, however, they 

 pass into the stomach through its abdominal orifices, and thence are 

 ejected through the mouth. In the viviparous Actinia, the young, devel- 

 oped at the base of the stomach, are expelled in the same manner.'-'* 



§50. 



II. Many Anthozoa, which have no general cavity of the body, have 

 external sexual organs. This is especially true of Hydra, where in the 



2 Raspail, loc. cit. i)I. XII. fig. 10-12, pi. XIV. of Alcijonidium. gelatinosum, Johnst. (Halo- 

 fig. 4-S, anil pi. XV. tig. 5. dactylus diaptianus of Farre), is quite remarka- 



3 Turpin and Gervais, Ann. des Sc. Nat. VII. ble; for he found tliem wanting in the isolated in- 

 18.37, pi. III. A. fig. 2-4, and pi. IV. A. fig. 1-6. dividual, but scattered here and there, in the form 



4 Wagner. IVie.;mann^s Arch. 1835, 1. Taf. III. of small round sacs, in the fleshy substance of the 

 flg. 1 ; also Ic Mies zoot. Taf. XXXIV. fig. 22. corallum — some being ovaries, others testicles. 



5 (iuatre/ages. Ann. d. Sc. Nat. loc. cit. pi. I. But he is in doubt whether or not their contents 

 fig. 7, anl pi. II. fig. 10. are emptied into the cavity of the body or upon the 



C Carus and Otto. Eriauterungstafeln, Ht-ft. IV. outer surfaces (Beitr. loc. cit. p. 46).* 



Taf. I. fig. 19 i also If't/^ner, Icones zoot. Taf. I Sm, for Alci/onella stagnorum, Mei/en (Isia, 



XXXIV. fig. 2. 1S2S, p. 1228). 



7 Milne Edwards. Ann. d. Sc. Nat. loc. cit. pi. ii Rathke has often found spawn in the stom- 

 XIV. fig. 4; pi. XV. fig. 6, 8, and pi. XVI. fig. ach of Actinia (Reise Bemerk. aus Taurien, zur 

 3-5. Morph. 1837, p. 10, and Beitr. zur vergleich. 



8 Ibid. p. 329, pi. XII. fig. 3, pi. Xin. fig. 2,7. Anat. u. Pliysiol. in the neuesten Schrift. d. na- 



9 Rymer Jones. Outlines, loc. cit. p. 36, fig. 9, turf. Gesellsch. zu Danzig, III. lift. IV. 1842, p. 

 after Lamouroux. 112). 



10 KoUiker''s observation upon the se.xual organs 



* [ § 48, note 10. J With the Actinina, some of which are situated the ovaries. With the Zoanthi- 



the lamellae whicli partition off the visceral cavity dae the relations are of the same general nature; 



are margined each i.., a white, capillary, convolut- but with the Tubipora, Dana found six spermatic 



ed cord., It is attached to the lamellae by a thin, to two ovarian lamellae. Sae Cc/Jia, Itx;. cit. p.43, 



mesentery-like membrane. These cords are the pi. XXX. fig. 3, b, c, d, e, f, and pi. LIX. fig. 1, b. 



testicles. Between the spermatic lamellae are oth- — Ed. 

 ers similarly arranged, which are the ovarian, on 



