POLYPES. 
59 
bling horn, an exudation from the gelatinous integument; 
and this tube, at every bud, takes the form of an open 
cell or cup (varying much in shape according to the 
species), into the cavity of which each individual polype- 
head can withdraw itself on alarm, and from the orifice of 
which it protrudes and expands when seeking prey. 
In the accompanying Plate, the figure a represents one 
of the most regular of these species ; and, therefore, one 
whose construction is peculiarly intelligible. It is a 
gioup of the Polype named La/medea geniculata, very com- 
monly found springing from the broad leathery leaves of 
the fingered tangle. Laminaria diejitata, that great olive- 
brown sea-weed that waves its huge fronds to and fro just 
below the level of the lowest spring-tides. The first ap- 
pearance of the Polype is a slender homy thread that 
creeps along the surface of the leaf, adhering firmly to its 
surface. Presently such a tiny budding stem as we have 
just described springs up from the root-thread, which con- 
tinues to creep on its way over the leaf, now and then 
bending its course at an abrupt angle, and sending up 
fresh stalks at regular intervals, which at length become a 
miniature forest. A few such stalks are represented at a, of 
ie natuial size ; and, at fig. b, one of these, or at least a 
poition of one, is shewn as it appears considerably mag- 
ed. The homy tubo is seen, with its cup-like cells: 
body of the Polype, a thread of gelatinous flesh, per- 
life^ 68 ^ le stem and the branches, maintaining a common 
■ at intervals, the polype-heads project in the manner 
its Uf S ' 6aCil 0CCU Py* n S its transparent cell, and displaying 
crow n of tentacles which radiate on every side. The 
°^ei cells are commonly empty, the polype-heads having 
