ANTHOZOA HELIANTHOIDA. 189 



single, viz. every individual is isolated and complete in itself, 

 and not organically associated with others, as the polypes of 

 the preceding orders are. They are also all oviparous, the 

 ova being generated in appropriated organs. According to 

 Spix, the ova, in the Actinise, form several grape-like clusters, 

 situated in the interseptal spaces, with ducts which open into 

 the base of the stomach by several apertures, and hence the 

 ova are presumed to gain their freedom by traversing the 

 stomach and mouth.* Blainville doubts this, being led from 

 analogy to believe it more probable that the oviducts may 

 open in the labial rim, as they do in the asteroid zoophytes.| 

 Delle Chiaje says that they terminate in the tentacula of the 

 Actinise ;J and Cavolini states, that in the Caryophyllia the 

 ova are discharged through small distinct openings between 

 each of the tentacula. Their natural passage of egress may 

 be considered to be undetermined, but it seems to be ascertain- 

 ed that they do, under certain circumstances, escape from the 

 body sometimes through the tentacula, or in apertures between 

 them, and sometimes through the mouth. Mr. Teale, after 

 vainly attempting to discover any proper oviduct, thinks it 

 probable that the ova, when sufficiently matured, " actually 

 burst their membranous envelope, and become lodged in the 

 interseptal spaces where they are exposed to the free access 

 and continued supplies of sea water, the grand stimulus to 

 their further development." 1 "^ The supposition readily ex- 

 plains certain facts which have given rise to an opinion of 

 their viviparous generation, for the young will be born alive if 

 the easy admission is made that some of the ova may have 

 their egress delayed until they have passed through their first 

 stages of evolution. That many ova, and probably by much 

 the greater number, escape previously to this is now well as- 

 certained. 



Mr. Teale's description of the ovaries differs also from 

 Spix's, and is very accurate. In Actinia coriacea he tells us 

 they form " elongated masses attached along the inner border 



* Cams, Comp. Anat. Trans, ii. 308, pi. i. fig. x. 



t Man. d'Actinologie, 79. 



$ Bull. desSc. Nat. xvii. 471. 



Edin. New Phil. Journ. i. 153. 



1 Leeds Phil, and Lit. Soc. Trans, i. 1 1 1 . Couch's Corn. Faun. iii. p. 689. 



