Laomedea. 
Z. HYDROIDA. 
153 
This species, in its most perfect state, rises to the height of 8 or 10 
inches. The stem is as thick as small twine, straight, opake, and 
composed of many tubular threads twisted together. It does not 
properly divide itself, but sends off branches from all sides, which are 
either opposite or alternate, and much ramified into diverging branch- 
lets, each of them marked with three or four rings at its base, and 
terminated with a bell-shaped polype-cell of a very thin corneous 
texture. A specimen of this description from Shetland, in the col- 
lection of my friend Dr Coldstream, is figured in Plate XXIII. 
But more commonly Laom. gelatinosa is found in a much hum- 
bler condition, and under a guise that requires for its discrimination 
from Laom. geniculata, a careful examination. It occurs thus in 
Berwick Bay, growing gregariously on the sides and under surface of 
stones lying in shallow pools between tide-marks, and seemingly 
giving a preference to those that contain an impure or brackish 
water. The shoots are all connected with one another by the ra- 
dicle fibre which creeps in an irregular manner along the rock ; they 
are rarely above an inch in height, simple or sparingly branched, 
consisting of a single tube of a light corneous colour and texture, 
ringed above the origins of the long twisted filiform pedicles on which 
the polype-cells are raised. These cells are deeply cupped, transparent, 
wfith a wide even margin. Vesicles urn- shaped, smooth, shooting 
from the axils of the pedicles. They are matured during the 
summer months, when we find them filled with ova of a circular flat- 
tish form, marked with a dark speck in the centre. At first they fill 
not more than half of the vesicle, but by their increase in size they soon 
come to occupy the whole cavity, and are ultimately extruded from the 
top, after which the empty vesicle soon disappears. The ova while 
in the vesicle are arranged round a central placentular column, and 
the lid which closes the vesicle is a mere dilatation of this column, 
which appears to be composed of two pieces soldered together, and 
bulged at intervals, where perhaps the ova are more immediately af- 
fixed in their immature state. 
The Polypes have about twenty long filiform tentacula roughened 
with minute tubercles placed in whorls. In their centre is the mouth, 
which assumes the shape sometimes of a rounded projecting tubercle, 
sometimes of a narrow column, and sometimes of a broad flat disk 
with a stricture under it simulating a neck. It leads directly to the 
stomachal cavity which is large and undivided, and I have occasional- 
ly witnessed within it currents of a fluid filled with minute granules, 
as has been more fully noticed by Mr Lister and Dr Fleming. 
Milne-Edwards, in the belief of there being a specific difference 
between the zoophytes described by Pallas and Fleming, has propos- 
