Beroe. 
RADIATA. ACALEPHA. 
503 
These terminated in the centre, each in an ovate head, apparently containing 
air. Immediately below each head, there were numerous twisted vessels, 
some of which contained a reddish fluid. The tube which descended from 
the summit, as it approached the centre, suddenly expanded, and sent off a 
branch to a vesicle on each side ; after which it appeared to unite with the 
one from the mouth. Each of the lateral vesicles terminated below in a blind 
cavity, which contained a glandular body, to the upper surface of which, se-. 
veral white threads were attached. The upper extremity of each vesicle was 
open, and terminated on the surface, on each side, in the space between two 
ribs. From each side of the vesicle, near its connection with the central ves- 
sel, there arose a tube, which, after dividing, sent a branch to each conti- 
guous rib. The cavity of these tubes, at their union with the ribs, appeared 
to be filled with a whitish coloured pulp. Each rib is furnished with a tube, 
uniting with it near the middle. In consequence of this peculiar structure, 
I could easily observe the water enter the tube at the summit, pass into the 
lateral vesicles, and go out at their external openings ; and, in some cases, 
the motion of the current was reversed. There did not appear to be any ex- 
ternal opening at the extremity of the tubes joining with the ribs, although 
water obviously moved backwards and forwards in them. While the animal 
w'as active, there were numerous small spaces in the different tubes where 
the contained fluid circulated in eddies. This was particularly observable 
towards the centre, and in the tube Avhich descends from the summit. I was 
unable to detect, with the naked eye, any structure in the tubes which could 
produce these partial motions ; and the orbicular form of the animal prevent- 
ed the application of high magnifiers. The species here described approaches, 
in many respects, to the Beroe ovata of Baster, Opuscula subseciva, vol. i. 
p. 123. tab. xiv. f. 5. It differs, however, in having only eight ribs, appa- 
rently smooth on the surface, with denticulated margins ; whereas the spe- 
cies which Baster notices has nine ribs, thickly set with moveable hairs. 
The season in which ours was found, would likewise intimate that it is distinct 
from Baster’s species, provided we attach much importance to his remarks. 
“ In nostris hsec Beroe invenitur littoribus, et in ipsis hujus urbis portubus, 
Aprili potissimum mense ; singularis enim variarum Medusse specierura pro- 
prietas est, quod alise aliis frequentissime inveniuntur mensibus.” Ellis ap- 
pears to have been acquainted with this species, when he says, “ The Beroe 
is a marine animal found on our coasts ; of a gelatinous transparent nature ; 
and of an oval or spherical form ; about half an inch to an inch diameter ; 
divided, like a melon, into longitudinal ribs, each of which is furnished with 
rows of minute fins, by means of which this animal, like the animalia infuso- 
ria^ can swim in all directions with great swiftness.” — Phil. Trans, vol. lix. 
p. 144. 
66. B. cucumis. — Body oblong, the oral aperture wide. 
Fab. Fauna Groen. 361. — B. fulgens. Macartney^ Phil. Trans. 1810, 264. 
t. XV. f. 1-8. — Shore of Kent. 
‘‘ This most elegant creature” (says Mr Macartney) “ is of a colour 
changing between purple, violet, and pale blue ; the body is truncated before 
and pointed behind ; but the form is difficult to assign, as it is varied by par- 
tial contractions, at the animal’s pleasure. I have represented the two ex- 
tremes of form that I have seen this creature assume. The first is some- 
what that of a cucumber, which, as being the one it takes when at rest, should 
perhaps be considered as its proper shape. The other resembles a pear, and 
is the figure it has in the most contracted state. The body is hollow, or 
forms internally an infundibular cavity, which has a wide opening before, and 
appears also to have a small aperture posteriorly, through which it discharges 
its excrement. The posterior two-thirds of the body are ornamented with 
eight longitudinal ciliated ribs, the processes of which are kept in such a rapid 
rotatory motion, while the animal is swimming, that they appear like the con- 
tinual passage of a fluid along the ribs. The ciliated ribs have been described 
