Beuoe. 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 

 was 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 which 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, Opv.scula 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, pi-ovided we attach much importance to his remarks. 

 " In nostris hasc Beroe invenitur littoribus, et in ipsis hujus urbis portubus, 

 Aprili potissimum mense ; singularis enim variarum Medusse specierum pro- 

 prietas est, quod aliae 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. 3G1 — 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 



