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' 

 tella mucedo, Cud.), 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 iu 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 borders 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 iae/''> AVith Verelillmn^^'' ^nH Alcyonium'^'^ these organs form mesen- 

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



3. In Alcyonidium elegayis '''- 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 diiFerent 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. pi. XII. fig. 10-12, pi. XIV. of Alcyonidium. gelatinosum, Johnst. {HaJo- 

 fig- 4:-S, and pi. XV. fig. 5. dactylus diaphanus of Farre), is quite remarka- 



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

 1837, pi. III. A. fig. 2-4, and pK IV. A. fig. 1-6. dividuals, but scattered here and there, in the form 



4 Warner. fVie^mami's Arch. 1835, 1. Taf. III. of small round sacs, in the fleshy substance of the 

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



5 Quatrefa^es. Ann. d. Sc. Nat. loc. cit. pi. I. But he is in doubt whether or not their contents 

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



6 Carus and Otto. ErlSuterungstafeln, Heft. IV. outer surfaces (Beitr. loc. cit. p. 46).* 



Taf. I. fig. 19; also ^fog-raer, Icones zoot. Taf. ^ See, fxw Alcyonella stasnorum, Meyen (Isis, 



XXXIV. fig. 2. 1828, p. 1228). 



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

 XrV. 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. 829, pi. XII. fig. 3, pi. XIH. fig. 2, 7. Anat. u. Physiol, in the neuesten Sohrift. d. na- 



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

 after Lamouroux. 112). 



lOKolliker^s observation upon the sexual organs 



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



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



are margined each bj a white, capillary, convolut- but with the Tubipora, Dana found si.\ spermatic 



ed cord. It is attached to the lamellae by a thin, to two ovarian lamellae. See Dana, loc. 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 ai'ranged, which are the ovarian, oq 



