ORIGINAL COMMUNICATIONS. 
On the Pupicettaria of the Ecuinoprermata. By WiLL1AM 
Biro Herapatu, M.D. Lond., F.R.S. London and 
Edinburgh. 
(With Plates IV. & V.) 
Turse remarkable forceps-like bodies have not received that 
attention from microscopists which their beauty and peculi- 
arities demand, and many observers have wholly mistaken 
their significance, as even the names by which they are known 
bear witness—pedicellus, originally meaning a little louse or 
parasite. It is evident that these bodies were formerly con- 
sidered parasitic to the animals on which they were found, 
and of independent vitality ; whilst their general form and 
appearance are nearly as much unknown to microscopists 
and naturalists, as must be acknowledged from the fact that 
one of these calcareous pedicellariz, on account of its remark- 
able resemblance in form to the head of a mammal, was even 
recently announced as such, and as having been found at the 
bottom of the Atlantic Ocean, in deep-sea soundings, by 
a celebrated well-known naturalist; this specimen having 
been exhibited by him at the meeting of the British Associa- 
tion, at Cambridge, and it excited considerable discussion 
amongst naturalists; some of whom were disposed to con- 
sider it to be “the dactylos or movable claw of a minute 
crustacean,” and various other opinions were formed of its 
nature. But Mr. Busk, froma comparison with the valves of 
one of the pedicellariz of Kchinus lividus, and another of 
Amphidetus communis, conjectured that it was the pedicel- 
laria of an unknown Echinus, in which view all must concur 
who compare the figure of the object given in the ‘ Microscopi- 
cal Journal,’ Vol. 1X, page 39, with the extensive series now 
exhibited of the author’s photographs of the various pedi- 
cellarize of our British Echinodermata. From these photo- 
graphs it will be seen that the object in question is a valve of 
that form called pedicellaria globifera, but that it does not 
belong to any of our British Echini, although closely resem- 
VOL. V.—NEW SER. N 
