54 



THE POLYPI. 



^^ 49, 50. 



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

 shape, and of a dark-brown color. In CristateJla mirabilis, Dal. [Crista- 

 tella mucedo, Ciiv.), 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 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- 

 wardsiaeß^ With Veredllum ^'^^ and Alcyonium'-''' these organs form mesen- 

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



3. In Alcyonidium elegaris ^^' and Tuhipora musica ^''' these organs are 

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

 cated mesenteric forrn.'^"^ 



§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. pi. Xn. fig. 10-12, pi. XIV. 

 fig. 4-8, and pi. XV. fig. 5. 



3 Turpin and Gervais, Ann. des Sc. Nat. VIT. 

 1837, pi. III. A. fiff. 2-4, and pi. IV. A. fig. 1-6. 



4 Wagner. fViegmann's Arch. 1835, 1. Taf. III. 

 fig. 1 ; also Icones zoot. Taf. XXXIV. fig. 22. 



5 Quatrefages. Ann. d. So. Nat. loc. cit. pi. I. 

 fig. 7, and r>l. II. fig. 10. 



tj Carus and Otto. Erlftuterungstafeln, Heft. IV. 

 Taf. I. fig. 19 ; also Wagner, Icoues zoot. Taf. 

 XXXIV. fig. 2. 



^ Milne Edwards. Ann. d. Sc. Nat. loc. cit. pi. 

 XIV. fig. 4; pi. XV. fig. 6, 8, and pi. XVI. fig. 

 S-5. 



« Ibid. p. 829, pi. XII. fig. 3, pi. Xm. fig. 2, 7. 



9 Rymer Jones. Outlines, loc. cit. p. 36, fig. 9, 

 after Lamnuroux. 



iO KüUiker^s observation upon the sexual organs 



of Alcyonidium gclatinosum, Johnst. (Halo- 

 dactyliis diaphanus of Farre), is quite remarka- 

 ble; for he found them wanting in the isolated in- 

 dividuals, but scattered here and there, in the form 

 of small round sacs, in the fleshy substance of the 

 corallum — some being ovaries, others testicles. 

 But he is in doubt whether or not their contents 

 are emptied into the cavity of the body or upon the 

 outer surfaces (Beitr. loc. cit. p. 48).* 



1 See, for Alcyonella stagnorum, Meyen (Isis 

 1828, p. 1228). 



'■i Rathki has often found spawn in the stom 

 ach of Actinia (Reise Bemerk, aus Taurien, zui 

 Morph. 1837, p. 10, and Beitr. zur vergleich. 

 Anat. u. Physiol, in the neuesten Schrift, d. na- 

 turf. Gesellsch. zu Danzig, 111. Hft. IV. 1842, p. 

 112). 



* 1 § 48, note 10. J With the Actinina, some of 

 the lamellae which partition off the visceral cavity 

 are margined each by a white, capillary, convolut- 

 ed cord. It is attached to the lamellae by a tliin, 

 mesentery-like membrane. These cords are the 

 testicles. Between the spermatic lamelhie are oth- 

 ers similarly arnuigeil, which are the ovarian, on 



which are situated the ovaries. With the Zoanthi- 

 dae the relations are of the same general nature; 

 but with the Tuhipora, Dana found six spermatic 

 to two ovarian lamellae. See Dana, loc. cit. p. 43,. 

 pi. XXX. fig. 3, b, c, d, e, f, and pi. LIX. fig. l,b 

 — Ed. 



