519 
sufficient to cause the emission of a vivid flash of beautiful greenish 
light. 
The author was aware that a source of fallacy might exist in the 
want of sensitiveness in the experimenter to faint luminous impres- 
sions, immediately after exposure of his own eyes to ordinary day- 
light ; and accordingly no conclusion was arrived at as to the absence 
of luminosity until the eye was rendered sufficiently sensitive by 
confinement for some time in the dark room. 
The absence, then, of luminosity in these animals during the day, 
is not due alone to the phosphorescence being rendered invisible by 
the stronger daylight, but to the fact that no light whatever is at 
that time emitted by the animal. 
The author also stated that the embryo, while still included within 
the egg, is eminently phosphorescent, and that the emission of the 
light is subject to exactly the same conditions as in the adult. He 
was of opinion that the ova and free embryos of the Beroe and other 
Ctenophora, are among the chief sources of the phosphorescence of 
the sea in our latitudes — an opinion which finds support in the 
immense number of ova produced by these monoecious animals, taken 
in connection with the countless multitudes of Ctenophora which at 
certain seasons of the year crowd the seas round our coasts. 
2. Contributions to our Knowledge of the Structure and De- 
velopment of the Beroidse. By Professor Allman. 
In this communication the author gave the results of some care- 
ful observations and dissections he had made of a species of Beroe 
( Idyia ), obtained in abundance during the last summer in the Firth 
of Forth. 
In the anatomy of the adult animal, several points were described 
which seem to have been hitherto either overlooked or imperfectly 
examined. In the digestive system, the author noticed the pre- 
sence of two richly ciliated membranous semi-elliptical flaps, which 
just before the stomach terminates in the narrow neck which leads 
into the bifurcating funnel, spring from its walls, and extend, by 
their free extremities, into the neck and commencement of the 
funnel. The equivalents of these flaps will doubtless be found in 
the two lips noticed by Milne Edwards in a similar position in Beroe 
ForsJcalii ; and the author is of opinion that they are also the 
4 A 
VOL. IV. 
