62 
LIFE, IN ITS LOWER FORMS. 
that is needful is to place in a vessel of sea-water a frond 
of sea-weed studded with the zoophyte, and in a few hours 
scores or hundreds will be seen, even with the naked eye, 
playing and dancing about in the most amusing manner. 
Fig. cl represents the embryo, very highly magnified. 
In structure the tiny animal, which, though just bom 
of a stationary zoophyte, is now swimming at will in a 
sprightly manner through the free water, is evidently a 
Medusa ; in all essentia] particulars being the very coun- 
terpart of one of those exquisitely delicate animals which 
Professor Forbes has so beautifully describedand portrayed 
in his “Monograph of the British Naked-eyed Medusa;.” 
It consists of an umbrella-shaped disk of translucent jelly, 
the diameter of which is about &th of an inch. Four 
vessels cross the disk at right angles, and from the centre of 
union there springs a fleshy peduncle, with a sort of neck, 
capable of many varied motions and many alterations of 
form. The margin of the disk carries twenty- four slender 
tentacles, exactly corresponding to those of the parent 
Polype, and essentially to those of the Hydra, beingstudded 
with warts, which analogy pronounces to be aggregations 
of barb-bearing capsules, instruments for arresting and 
killing prey. At the bases of the tentacles, arranged at 
certain definite points on the margin of the disk, are placed 
eight beautiful organs, which are doubtless the seats of a 
special sense. Each of these organs consists of a trans- 
parent globe, not enveloped in the substance of the disk, 
but so free as to appear barely in contact with it. In its 
interior is borne a smaller globule or lens, of high refrac- 
tive power, placed a little towards the outer side. Almost 
every one, on first beholding these organs, would unhesi- 
