184 HERAPATH, ON THE PEDICELLARIZ OF ECHINODERMATA. 
On pressing out a portion of this fleshy peduncle it is easy 
to find the long, twisted, muscular ropes, running through 
the fleshy mass to the base of each pedicellaria, there dividing 
into two branches, one for each blade of the forceps. Polar- 
ized light renders this structure more evident. These 
forcepiform pedicellariz are also found in solitary individuals 
attached to the marginal base of the fenestrae. The best 
method of seeing these pedicellariz is to dissect off the dorsal 
integument of the star-fish, dry it between two plates of glass, 
boil it in turpentine, and mount it in a cell in thin Canada 
balsam, boiling to expel air-bubbles, and placing a glass cover 
on, as usual. Polarized light exhibits these calcareous organs 
splendidly. 
In addition to these pedicellariz, common to both the 
Uraster rubens and glacialis—but all are of far larger size 
in the latter species—we find an enormously large “ maxille- 
form” pedicellaria in the glacialis, which is peculiar to this 
species ; it appears in greatest numbers along the margin of 
the ambulacral groves, and is usually “solitary.” It is 
coarsely dentated around the jaw-like edge, with large serrated 
teeth, interlocking with those of the opposing blade, and its 
base is attached to the double, cup-like, terminal joint, as in 
the mandibulate and forficiform varieties, which it differs from 
in possessing a rounded, expanded, jaw-like end, instead of a 
pointed conical tip. These pedicellarize have not been previ- 
ously described or figured by any observer. 
It is usually pedunculated, the peduncle being long, fleshy, 
and tubular, without any calcareous style. - 
This pedicellaria is also valvate in form, like the mandibu- 
late and forficiform varieties. 
The following measurements have been very carefully made 
in 10,000ths of an English inch. 
URASTER RUBENS. URASTER GLACTALIS. 
— edt [SS 
Ped. forficiforma: . Mean 0262 oo Meh ay 
- 2 ax. ... 0820 Max. wo. 0490 
A . Min. 1. 0200) “Min: Ji 20206 
P. forcepiforme . Mean ‘0090  ... Mean ‘0160... 
an np Miaxe = 830093 Max: a), sOL66 
Pe . Min. ... ‘0086 Min. es, tee 
P. maudibulatze . Mean ‘0160 A 
a . Max. Bet O186 
a . Min. Pa O16 
P. maxilleforme  . Mean -:0713 a 
3 ; Max. siete) CBE 
” : Min. a *0420 
(To be continued.) 
