202 ZOOPHYTA HELIANTHOIDA. 



ment."* The supposition readily explains some 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 pro- 

 bably by much the greater number, escape previously to this is 

 now well ascertained. 



Mr Teale's description of the ovaries varies also from Spix's, 

 and is very accurate. In Actinia gemmacea he tells us they 

 form " elongated masses attached along the inner border of 

 most of the leaflets. Each ovary is composed of several hori- 

 zontal folds or plaits, which, when unfolded, show this structure 

 to be about three times the length it assumes when attached to 

 the leaflet. By carefully spreading out these folds, the ovary, 

 with the assistance of a lens, is seen to consist of two very de- 

 licate layers of membrane, enveloping a closely compacted layer 

 of ova. After enveloping the ova, the membranous layers are 

 placed in apposition, and form a kind of mesentery, by which 

 the ovary is attached to the internal border of the leaflet. The 

 two layers afterwards separate to pass one on each side of the 

 leaflet, thereby lining the interseptal spaces from which this 

 membranous investment is prolonged into the tentacula, as well 

 as into the cavities within the structure of the lip and mouth. 

 At the summits of the tentacula, and of the tubular eminences 

 of the lip, the membrane becomes continuous with the common 

 integument, whilst at the inferior part of the interseptal spaces 

 it is continuous with the digestive sac. The breadth of the 

 ovaries is nearly uniform from the top to the bottom. Some ir- 

 regularities are occasionally observed in their attachment to the 

 leaflets. Sometimes one leaflet supports two ovaries, and not 

 unfrequently two neighbouring ovaries are continuous with each 

 other at their inferior extremities." '\- 



The period of propagation is probably, in most Helianthoida, 

 not limited to any particular season. According to the obser- 

 vations of Cavolini the Caryophyllia matures its ova in spring ; 

 and it is only at this season that I have found the Lucernarise on 



* Leeds Phil, and Lit. Soc. Trans- i. IIL f Lib. supra cit. p. 104. 



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