ZOOPHYTA HELIANTHOIUA. 201 



nutrient parts may be by its means fitted for more immediate 

 assimilation, for as there is neither circulating nor lymphatic sys- 

 tems, the absorption of the nutrient fluids must be made direct- 

 ly from the stomach itself. By the contraction of the periphery 

 of the body, this water is again expelled at pleasure through the 

 tentacula in a continuous stream or in jets, and if the contrac- 

 tion is sudden and strong, the water may be thrown out with 

 such force as to rise to the height of at least a foot. It is re- 

 markable that the water does not escape from all or the great- 

 er number, but only from a few of the tentacula. Whether 

 any part escapes by the mouth is doubtful. 



All the native species are single, viz. every individual is iso- 

 lated 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 or- 

 gans. 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 tra- 

 versing 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 zoo- 

 phvtes. -f- Delle Chiaje says that they terminate in the tentacula 

 of the Actiniae ;% 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 mem- 

 branous envelope, and become lodged in the interseptal spaces 

 where they are exposed to the free access and continued sup- 

 plies of sea water, the grand stimulus to their further develope- 



" Cams, Conip. Anat. Trans, ii. 308, pi. i. fig. x. 



f Man. d'Actinologie, 79- 



f Bull, des Sc. Nat. xvii. 471. 



§ Edin. New Phil. Journ. i. 153. 



