CTENOPHORES. 
477 
or as long as life lasts. Storms, however, destroy them. The largest specimens 
are, as a rule, found in waters sheltered from the wind. They are to he seen 
throughout the whole year, but are most plentiful during the spring months, and 
become rarer towards summer, when some species, such as the Venus’ girdle, almost 
completely disappear. In the early autumn, however, great swarms appear, 
especially of Cestus and Beroe. After a spring of active fertility, the larvae, at the 
beginning of the hot months, sink down to greater depths, where they grow into 
adults, and come to the surface again in swarms in autumn. 
Insignificant as these delicate creatures may appear, they delight the eye, 
both while living and after death, by their luminosity. This is principally 
displayed in the walls of the canals below the ribs. It is a curious fact, and one 
unique as regards luminous marine animals, that Ctenophora, after being exposed 
for only a short time to the light of the sun or the moon, or to artificial light, when 
suddenly brought into a dark room, are incapable of giving light. Allman is of 
opinion that the Beroidce and their broods must be regarded as the principal 
source of marine phosphoresence on the English coast. 
The Ctenophora are hermaphrodite ; sexually mature animals of many species 
being found throughout the whole year, while others occur only in sjwing, summer, 
or winter. The young pass through a metamorphosis, or have larval stages which 
precede the definite form. In at least one species (. Eucharis multicornis ) sexually 
mature larvae, or larvae which are capable of reproduction as such, also occur; these, 
when completely developed, become once more capable of reproduction as adults;— 
a method of multiplication which has been called dissogony. 
The most interesting, if not the most beautiful, of the Ctenophora are the 
Beroidce, —shown in the coloured Plate,—which resemble Phrygian caps in shape. 
In section, they are oval; the mouth is wide, and they have no capturing filaments 
or tentacles, and therefore no adhesive cells. They attain a size of 8 inches, and are 
of a delicate red colour, which appears marbled. This appearance is due to the 
branching of the eight principal canals above described, the ramifications forming 
a network. Beroe forskalia, shown in the Plate, is found in the Mediterranean. The 
Beroidce are carnivorous, feeding on their own relations of other genera. On one 
occasion, a large Eucharis was placed in a basin with a Beroe forskalia, not half 
its size, in a fasting condition. The latter, attracted by its wonted food, began 
swimming round the Eucharis in large circles, with wide open mouth. On 
approaching its victim, it darted at it, and seized it. The swimming-plates of the 
Eucharis beat helplessly, when, to the astonishment of the observers, this large 
creature was completely mastered by the Beroe, which in less than a quarter of an 
hour succeeded in swallowing its victim, and, distended like a balloon, lay at the 
bottom digesting it. 
The Cydippidce are conical, or barrel-shaped, with the ribs uniformly developed, 
and two opposite tentacles, one on each side. The beautiful creature figured in the 
Plate is Hormiphora plumosa from the Mediterranean. The remarkable Venus’ 
girdle ( Cestus veneris), shown in the annexed illustration, is so called because the 
body is lengthened out sideways like a ribbon, so that the mouth is found on the 
under edge of the ribbon half-way along it. This girdle-shaped, transparent 
creature, iridescent in the sunshine, is a dazzling sight. The ribbon is edged with 
