168 Objects for the Microscope. 



vals large capsules or ovarian vesicles rise from the base of 

 a smaller cell. In life this horny skeleton was filled with 

 a living pulp, and each tiny tube right and left was the 

 abode of a beautiful white creature called a Polype, which 

 rose up and threw out eight or ten fine tentacula, or 

 feelers, drawing food into a mouth placed in the centre of 

 these tentacles. From the mouth there was a digestive 

 sac, or stomach, communicating with the stem, and a cir- 

 culation of fluid went on throughout the polypidom, that 

 is to say, the branch of cells we have described, though 

 each Polype had an independent life. 



It has been observed, that at the base of the Zoophyte 

 stomach there is an orifice closed by a contracting and 

 dilating sphincter muscle, and through this the digestive 

 food is propelled to the stem, after enough has been appro- 

 priated by that Polype, besides which a spiral movement 

 of particles is seen in the stem, somewhat resembling the 

 rotation in Chara. 



The manner of propagation and of growth is very 

 remarkable. Those ovarian pear-shaped vesicles you may 

 see here and there on the branches contain buds, or 

 gemmaB, which, when mature, escape and swim freely in 

 the great ocean. Their form is most unlike that of their 

 parent ; they are called Medusyides, and in turn produce 

 fertilised ova ; these being edged with cilia3 move for 

 several hours in the water, and then, fixing on sea-weed, 

 rock, or stone, develop into a polypidom like this spray 

 of Sertularia. When the ovule fixes, minute fibres are 

 observed to proceed from the under side, and the pulp 

 dilates and ascends, covered by the horny substance, inside 

 which the dark pulp runs like a thread. At a certain fore- 

 ordained point it stops, becomes bulbous, a tube or cup 

 (according to the species) forms gradually, whilst the pulp 

 is fashioned into the Polype with little knobs lengthening 

 into tentaculse, which no sooner are complete than they are 

 thrown forth for food ; and the nourishment, instead of 

 increasing the size of the Polype, is passed to the stem, 

 and a second cell buds forth on the opposite side, or the 

 stem is prolonged a little, according to the plan of the 

 species. Look at the next slide 



