} 
69 
has, under favourable circumstances of observation, been more 
or less visible. In order to witness it in perfection the fibre 
must be on the stretch, for when it is torn from its attachments, 
or lies relaxed in the bottom of the cell, the striae become very 
obscure. When the broken extremity of a fibre is examined, 
the fracture will be found to have occurred in a plane perpen- 
dicular to the axis of the fibre, never exhibiting an uneven 
or lacerated appearance, and a marked tendency to separate 
into disks may be recognised in the detached and broken fibre. 
When the fibre is in an uncontracted state it would seem to 
be perfectly cylindrical, and the normal act of contraction is 
so momentary that its condition during this state cannot be 
witnessed. When, however, the living polypide is torn from 
its cell, the ruptured fibres, which continue attached to its body, 
are thrown into a state of spasmodic contraction; and then 
it will be seen that they lose their cylindricity, and become ir- 
regularly swollen at intervals, while the whole fibre has much 
increased in thickness. In this condition also they may be 
observed to be obscurely striated. The swellings here visible 
in the contracted fibre are quite different from the peculiar 
knots described by Dr. A. Farre in the muscles of the marine 
polyzoa. Such knots do not exist in the fresh-water species, 
at least I have never seen them, with the exception, perhaps, 
of certain little swellings which may be occasionally witnessed 
_ in the parietal muscles of Paludicella, and in the superior pari- 
eto-vaginal muscles of Plumatella. In Paludicella I have wit- 
nessed a curious phenomenon presented by the muscular fibre. 
In this polyzoon the fibres of the great retractor muscle, while 
lying relaxed in the bottom of thecell after the retraction of the 
polypide, may frequently be seen to present a smgular motion, 
impressing you with the idea of a cluster of writhing worms.” 
Rev. W. P. Moore read a description of the Vitrified Font 
of Shantamon, in the county of Cavan, and at the same time 
presented specimens of the stone of which the font is composed. 
