BEPEODUCTION OF CERIANTHUS MEMBKANACETJS. 77 



In both sexes the reproductive apparatus consists of riband-like convo- 

 lutions attached by delicate membranous folds to the free margins of 

 the septa, and filled with multitudes of the granular-looking bodies 

 above mentioned, which in the females are the ova, in the males the 

 spermatic capsules. In neither sex is there any excretory duct ; so that 

 the eggs, when mature, must escape immediately into the general cavity 

 of the body by bursting through the delicate membranous envelope in 

 which they are enclosed. The whole exterior of the organ is densely 

 ciliated. 



When examined under the microscope, the granules extracted from 

 their investment are found, in the male, to contain immense numbers of 

 caudate and very active spermatozooids, while those of the female are 

 real ova, of spherical shape, and furnished with a distinct yelk and 

 germinal vesicle. 



(171.) It is during the months of August and September that the 

 generative system of our native species is in full activity and develop- 

 ment. The ovum, it would seem, when arrived at maturity, breaks loose 

 from the ovarian nidus ; and as the number of males in a given locality is 

 pretty nearly the same as that of the females, and they are always more 

 or less found in company notwithstanding their sedentary habits, the 

 eggs of the female would seem to be impregnated by the seminal fluid 

 of the other sex, diffused through the surrounding water. 



(172.) In Cerianihus membranaceus, however, a complete hermaphro- 

 ditism exists, all the convolutions of the reproductive ribands being 

 equally supplied with both the male and female elements of generation, 

 in the shape of minute capsules, some of which enclose an ovule, whilst 

 the others are filled with spermatozoa. These two kinds of capsules 

 are scattered promiscuously, without any regular order, but always so 

 that the ovigerous and spermatogenous organs are closely in contact. 

 The ovules on quitting their ovarian nidus fall into the general peri- 

 visceral cavity, where they may be found of a spherical or oblong shape, 

 and each presenting a distinct Purkinjean vesicle. The act of fecun- 

 dation in this case appears to take place in the ovarian laminae, and 

 probably by the rupture of the delicate walls which circumscribe the 

 contents of the male and female capsules. The eggs found in the 

 ovaria are round and of a yellow colour, resembling minute grains of 

 sand, and densely ciliated. There exists a considerable opening in the 

 base of the stomach, whereby a free communication is established 

 between the interseptal spaces and the general abdominal reservoir, 

 through which the young Actinia3 are expelled in a very advanced state of 

 development into the stomach, and from thence pass through the mouth 

 into the surrounding water. The smallest germs are semi-opake spherical 

 bodies, while the more advanced present every gradation of form from 

 the simple sphere up to the complete tentaculate polyp. The largest are 

 about the size of peas. On section they present appearances similar 



