THE HYDROID MEDUSiE. 
343 
has been described as occurring in a few cases, we are justified, 
I think, in waiting for further testimony before coming to any 
positive conclusion on the subject. As sense-organs make their 
appearance along with a free existence, we should naturally 
look for the dawn of the nervous system at the same point. 
So much may suffice as to the general plan on which the 
Hydroid medusa is organized. I wish to avoid unnecessary 
detail, and to fix attention on the cardinal points of structure, 
and especially to emphasize what may be called the artistic 
and aesthetic aspects of my subject. No technical description, 
however minute and accurate, can enable us to realize the dis- 
tinctive beauty of these fragile beings. Not merely are the 
forms graceful, and the curves faultless, and the colours vivid, 
but an additional charm is imparted to all of them by the deli- 
cate and transparent material in which they are presented. 
Perhaps the portrait of an individual carefully executed may 
give the best idea of the kind of beauty that belongs to these 
“ wandering buds,” and may serve to justify the enthusiasm of the 
naturalist about them. I will select as my “ sitter ” a medusa, 
certainly one of the most lovely of its kind, which made its ap- 
pearance for two successive years in a friend’s tank, but which we 
were never able to trace to the parent stock (Plate LXXXVIIL, 
fig. 2). No doubt in some chink or cranny a charming little 
colony of polypites was concealed, which supplied the annual 
medusan brood, but it baffled our keenest search. I am not 
aware that the pedigree of the form which I am about to de- 
scribe has ever been made out ; it is probably one of the un- 
attached.'^ Imagine, then, a minute crystal globe, the surface of 
which is thickly dotted over with thread-cells, making it ap- 
pear as if delicately frosted ; from the free margin hangs a 
graceful fringe, composed of twenty beaded tentacles, springing 
from as many bosses of a brilliant green with metallic lustre, 
which girdle it as with a belt of emeralds ; amongst them are 
placed a number of the supposed eyes, each with its retractile 
corpuscle ; the pendulous sac in the centre of the dome is dyed 
with the richest carmine, and tipped with the purest white, 
while the ovaries on the course of the radiating canals, shower- 
masses of pink through the walls of its translucent bell. The 
colours are wonderfully brilliant, and the green tentacular 
bulbs almost glitter like gems. It was the prettiest sight to 
watch this little hydroid, with its painted and jewelled disc, 
now darting through the water with contracted arms ; now 
sinking slowly, like a balloon, with some of its tentacles ex- 
tended laterally as if to regulate its descent, and some hanging 
* It is, no doubt, tlie reproductive zooid of a Campanularian Hydroid, and 
may belong to the Genus Campanidzna , or a near ally. 
