8 ORGANS OF SENSE. 
1-200” in size. The males cannot be distinguished from the females either by shape or size 
of the body, or by the form of the sexual glands.” Will fancied these glands had a greenish 
glitter in the male, which was not present in the female. “The testicles are likewise twisted 
sacs filled with spermatozoa. The latter consist of a thick oblong body, measuring 1-800” 
and an extremely slender, long tail, which is only visible during vibration.” Will found at all 
times as many males as females. 
Organs of Sense.—The lips and their appendages, the marginal tentacula, and the bulbs 
at their bases, may be enumerated under this head. The lips and the tentacula are instruments 
of touch and prehension, the former chiefly for the purpose of seizing the animal’s prey, and 
sometimes, as I have seen in the case of a Geryonia, for anchoring the body. The lips vary 
much in form. They are sometimes (as in Circe, most species of Thaumantias, and 
Polyxenia) simple lobes ; in other cases (as in Zurris, Geryonia, and Oceania) fimbriated lobes ; 
in Bougainvillea and Lizzxia, they are furnished with single or branched tentacular processes, 
reminding us of the curious gland-tipped cirrhi, which are so conspicuous in the genus 
Cassiopeia among the higher Discophore, and which were long supposed, and are usually 
still described to be roots or suckers for the purpose of absorbing nourishment. In Sarsia, 
Slabberia, and Steenstrupia, the lip is a simple ring around the orifice of the tubular digestive 
cavity. The tentacula in all our British examples of the naked-eyed Meduse, are simple and 
usually filiform, though highly contractile, and in some species often reduced almost to a 
point. In Slabberia we have an abnormal form of these organs, their termination presenting 
the appearance of a bulb. In Luphysa, the single tentacle is clavate and different in structure 
from that of any other British genus. In the same curious form all the tentacles except one are 
aborted, a remarkable modification seen also in Steenstrupia. In a new species of Geryona, 
here figured, alternate tentacles are glanduliferous. In not a few species there are two 
varieties of tentacles placed in a single series round the margin, but the majority have the 
tentacles only of one kind. 
At the base of the marginal tentacula or cirrhithere are present in a great many of these 
animals coloured spots or bulbs. In some species (as in 7’haumantias pilosella, Slabberia 
halterata, Willsia stellata, Lizxia octo-punctata, &c.) these points are very strongly coloured, 
and from their magnitude indicate the course of the animal when in motion, appearing like 
a circle of gems in the water. Where some of the tentacula are aborted (as in Steenstrupia 
and Huphysa), they are not aborted with these organs, but are all conspicuously developed ; 
in many forms only certain tentacles have bulbs at their bases. In other forms, the tentacula 
are present and highly developed, but no coloured spots or bulbs are seen at their bases, as in 
certain kinds of Geryonta and Circe. When these bulbs are examined under the microscope, 
we find their organization more complicated than at first glance it would seem to be. In the 
majority of species, perhaps in all, these bulbs, whether conspicuous from colouring or not, 
contain a small cavity quite distinct from any coloured spot which may be present. The 
former is the ofolitic vesicle, the latter the ocellus. 
The ofolitic vesicle, which, from analogy and its peculiar structure, is considered an 
organ of hearing, is a small spherical sac developed in the midst of the granular substance of 
the bulb, and containmg more or fewer mimute vibrating bodies. Will has described the 
otolitic vesicle and its contents in a Geryonia as follows: ‘‘' The auditory vesicles are seated 
