No. 376.] SARCOSTYLES OF THE PLUMULARIDEZ. 229 
writers. I have on many occasions noted that the sarcostyles 
are very active after certain parts of the colony have been 
mutilated or where the hydranths are undergoing disintegration. 
While studying Plumularia pinnata at Plymouth I saw aston- 
ishing exhibitions of activity on the part of the sarcostyles in 
the vicinity of mutilated gonangia. Their extensibility was in- 
credible and apparently without limit. They would climb over 
the top of the gonangia and scour the inside, they would wind 
round and round the stem and branches in a’ perfect maze of 
apparently protoplasmic threads, and yet be able to unsnarl 
themselves with the greatest ease and afterward disappear 
entirely. Dead hydranths seemed particularly attractive to 
them, and it appeared as if they actually devoured or in some 
way absorbed the organic matter of the disintegrating polyps, 
so that not a trace remained within the hydrothecz in a very 
short time after the sarcostyles attacked them. 
4th. Holding together adjacent corbula leaves until their 
edges unite. This is a novel use of the sarcostyle, discovered 
by myself while working out the embryology of the corbula, or 
fruit receptacle, of Aglaophenia pluma at Plymouth. The cor- 
bula is a pod-shaped structure made up of a number of ribs or 
leaves, which are separated first, but afterward coalesce to form 
the mature corbula. Along the edges of these leaves are rows 
of nematophores. 
While examining a young corbula of a living colony, I no- 
ticed that the sarcostyles along the edges of the leaves were 
exceedingly active and that they were stretching across from 
one leaf to the next, to which they adhered by their adhesive 
ends. “It appeared as if these sarcostyles served as a tem- 
porary attachment to hold the edges of the two leaves together, 
while the edges themselves were connected by trabecule of 
coenosarc which rapidly formed a stronger and permanent con- 
nection. The perisarc of the edges of the leaves seemed 
exceedingly thin and in places appeared to be wanting. A 
contact having been established between the adjacent leaves, 
the permanent attachment was soon formed and the ccelomic 
cavities of the leaves established connections at these points. 
