SEA-NETTLES. 105 
giving off three nerves, of which the largest ran lengthwise between 
two bands of cilia} close to the external surface of the body; but a 
later observer, F'. WILL, was not so fortunate as to find this system 
of nerves. On the contrary he detected a conical ganglion above 
the funnel-shaped structure from whence the water-canals arise, 
consequently opposite to the mouth. From this ganglion many 
fine threads arise, to be distributed to the substance of the body 
and its different parts. In the same situation Minne Epwarps also 
Saw a ganglion in the genus Lesweuria, from which numerous 
nerves, collected into four bundles, arose. 
EHRENBERG considers the eight prominent organs, situated in 
Meduse at the edge of the disc, to be eyes: they contain a sandy 
or stony concrement, a quantity of minute hexagonal prismatic 
erystals composed of carbonate of lime. Such calcareous concre- 
ments are often found in the animal organism in the neighbourhood 
of nerves; as for instance in Frogs by the sides of the vertebral 
column near the exit of the spinal nerves. A red pigment which 
moreover generally distinguishes these marginal corpuscles, (it is 
sometimes wanting,) caused EHRENBERG to conjecture that they 
were eyes*. There is more probability in KorLurker’s idea, that 
they are to be considered as auditory organs‘. Even in vertebrates 
little stones or grit of carbonate of lime are found in the auditory 
sac or vestibule of the membranous Labyrinth. In Beroé and the 
allied genera only a single organ of the sort is found, a pedunculated 
vesicle with calcareous crystals at that end of the body which is 
opposite to the mouth’. 
The apparatus for motion consists of transparent muscular 
fibres, having sometimes a longitudinal, sometimes a circular 
course: they exhibit the same microscopic transverse stripes which 
are characteristic of the voluntary muscles of higher creatures®, 
Several of the Animals belonging to this Class are phospho- 
rescent. According to Enrenpere the Arabians on the Red Sea 
1 Trans. of the Zoolog. Soc. London, I. 1833, p. 10. 
2 Ann. des sc. nat. 2e Série, Tom. xvi. Zoolog. p. 206. 
3 Die Akalephen, s. 4. 
4 FRORIEP’s Neue Notizen, xxv. Bd. (Januar. 1843) s. 81—84. 
5 Minne Epwarps, |. 1., Witt, Hore Tergest. s. 45, 46. 
§ Wacner Bau der Pelagia noctiluca ; his Tab, Zoot. Xxx. fig. 30; Wit, 1. 1. 
s. 46—49. 
