PEDICELLAKIZ OF ECHINODERMATA. 181 
kindly supply him with specimens of the following Echino- 
derms—Spatangus purpureus, Echinus lividus, E. melo, 
and other of the rarer forms met with on our coast. He 
is also desirous that they should be freshly dredged, as in the 
cabinet the pedicellariz almost always drop off and are 
lost. He finds that dried powdered salt is the best material 
in which to pack them for his purpose. 
It only remains to conclude these introductory remarks by 
sincerely thanking the following friends and gentlemen for 
their kind assistance, viz., the Rev. A. Percival, of Scilly ; 
Professor Wyville Thomson, of Belfast ; Dr, Steele, of Dublin ; 
Mr. Gallienne, of Guernsey; Mr. C. Stewart, of Plymouth ; 
Mr. Bean, of Scarborough; Mr. Leipner, of Clifton; Mr. 
A. $8. Reed, of Tenby; and more especially the Rev. A. M. 
Norman, of Houghton-le-Spring; to all of whom the author 
is indebted for various valuable specimens of our British 
Echinodermata. 
ASTERIAS RUBENS (Linneeus). 
URASTER RUBENS (Forbes). 
The late Professor Forbes, in describing the pedicellariz 
of the Uraster rubens, says—“'Those on the body and upper 
spines differ in shape from those on the spines immediately 
bordering the avenues. The former are much shorter and 
blunter in the blades than the latter. The calcareous forceps 
of which their heads consist are united in an integument of 
a soft, granular tissue, which envelopes the forceps when 
closed; and this apparatus is mounted on a bulging body 
of a similar substance, which crowns the round and 
flexible peduncle, sometimes simple, sometimes branched, 
each branch having a similar termination. He could 
detect no vibratile cilia on their stalks, but there appeared 
to him to be ciliary motions within the blades. When 
the star-fish is alive the pedicellariz are continually in 
motion, opening and shutting their blades with great 
activity ; but when cut off they seem to lose that power. If 
they be not distinct animals, as Miiller fancied, for what 
purpose can they serve in the economy of the star-fish? If 
they be parasites, to what class and order do they belong? 
What is their nature, what their food? Truly these are 
puzzling questions. These organs, or creatures, have now 
been known for many years, have been examined and 
admired by many naturalists and anatomists, have been 
carefully studied and accurately delineated, and yet we know 
not what they are. This is but one of the many mysteries 
of natural history, one of those unaccountable things which we 
know and know not, of those many facts in nature which teach 
