634 
RADIATA. 
cies of Medusaa, two of Lizzia and two of Sarsia, have the power of producing young animals by 
direct gemmation, and their development from a zoophytic form has not yet been observed. In 
Lizzia and Sarsia geimyiifera the buds are produced from the stomachal peduncles ; but in the 
other species of Sarsia^ S. proUfera^ they originate from the bulbs at the base of the tentacles, 
where they may be seen attached in all stages of development. "What strange and wondrous 
changes !" says he, after detailing his observations upon the last-mentioned minute Medusa. 
" Fancy an elephant with a number of little elephants sprouting from his shoulders and thighs, 
bunches of tusked monsters hanging, epaulette-fashion, from his flanks, in every stage of advance- 
ment ! Here a young pachyderm, almost amorphous ; there one more advanced, but all ears 
and eyes ; on the right shoulder a youthful Chuny, with head, trunk, toes, no legs, and a shape- 
less body; on the left, an infant better grown, and struggling to get away, but his tail not sutB- 
ciently organized as yet to permit of liberty and free action ! The comparison seems grotesque 
and absurd ; but it really expresses what we have been describing as actually occurring among 
our naked-eyed Medusae. It is true that the latter are minute ; but wonders are not less won- 
derful for being packed into small compass." 
Wonderfully beautiful are many of these creatures inform and color, but, as we have before stated, 
the amount of solid matter contained in their tissues is incredibly small. The greater part of their 
substance appears to consist of a fluid, diflering little, if at all, from the sea-water in which the 
animal swims, and v^'hen this is drained away, so extreme is the tenuity of the membranes which 
contained it, that the dried residue of a jelly-fish weighing two pounds, which was examined 
by Professor Owen, weighed only thirty grains. Yet these creatures are capable of executing 
movements with considerable vivacity — their disc contracts and dilates alternately by the action 
of .a band of what must be regarded as a muscular tissue — their tentacles are capable of seizing 
upon and destroying, by a subtle venom, animals of far more complicated structure than them- 
selves, and their delicate stomachs have the powder of speedily digesting the victim. In fact, in 
spite of the extreme delicacy of their texture, the MedusfB are among the most voracious inhab- 
itants of the ocean. Small fishes and Crustacea, and all the infinite multitude of minute marine 
creatures, are seized and paralyzed by their deadly arms; and as the mouth and stomach are 
capable of almost indefinite dilation, the size of their prey often appears exceedingly disproportion- 
ate. Of the voracity of one of the most delicate and beautiful s^oecies of the small Medusae inhabit- 
ing the British shores, the Sarsia tubulosa, a little creature of the size and shape of a very small 
child's thimble. Professor Forbes speaks as follows : " Being kept in a jar of salt water with small 
Crustacea, they devoured these animals, so much more highly organized than themselves, vora- 
ciously, apparently enjoying the destruction of the unfortunate members of the upper classes 
with a truly democratic relish. One of them even attacked and commenced the swallowing of a 
Lizzia octopunctata., quite as good a Medusa as itself An animal which can pout out its mouth 
twice the length of its body, and stretch its stomach to corresponding dimensions, must, indeed, 
be ' a triton among the minnows,' and a very terrific one too." 
Professor Forbes separates the Medusae into two great divisions, which we shall adopt as orders. 
In the first of these the ocelli, or eye-like spots, surrounding the margin of the disc, are pro- 
tected by more or less complicated membraneous hoods or lohecl coverings, while in the second 
these organs are naked. Hence the former are called Stegano-plittialmata, Covered-eydd^iha latter 
Gynino'phthahnata, or Nalced-eyed. In the latter the ocelli, when present, are always placed on 
the bulbs at the base of the tentacles, and frequently also on the interstices between them. In 
the first order, on the contrary, they are always placed between the marginal tentacles. 
ORDER 1. STEGAIf OPHTHALMATA. 
The Medusge of this order often attain a gigantic stature : the Bhizostoma Cuvieri, a British 
species, measures two feet, or even more, in diameter, while some of the inhabitants of tropical 
seas are said to attain a still larger size. In calm weather they often swim close to the surface 
of the sea, in such multitudes as to impede the motion of a boat through the water. Such a 
