$$ 38, 34. THE POLYPI. 13 
CHAPTERS III. AND IV. 
NERVOUS SYSTEM AND ORGANS OF SENSE, 
§ 33. 
As yet only a very rudimentary and imperfectly distinguished nervous 
system has been made out in the Polyps; this consists of round masses, 
which are regarded as composed of nervous matter (ganglia), situated in 
the parenchyma. A ganglion of this kind has been supposed to have been 
observed about the mouth.” - 
§ 34. 
Investigations upon their organs of sense have not been more suc- 
cessful. However, the sense of touch appears developed over the whole 
surface of the body, but specially so in the extremely irritable arms and 
tentacles. But, as yet, no tactile nerves have been found in these parts. 
In the same manner, light, to which these animals show a greater or less 
sensibility, is perceived rather by the general surface of the body than by 
special organs. 
There are, however, in some species, at particular stages of development, 
during which they swim freely about, certain nicely-defined bodies situated 
upon the sides of the body, and which may be regarded as special organs 
of light and sound. This is the case with Syncoryne ;™ and Coryne has in 
their place four red organs which correspond exactly to those found on the 
border of the disc of the pulmograde Acalephz, and which have been re- 
garded as organs of sense. . 
The organ seen at the base of the six arms of Eleutheria dichotoma 
has quite the appearance of an eye; 
1A double cesophageal ganglion has been ob- 
served by Dumortier (Mém. sur Anat. et la 
Physiol. d. Polypiers composés d@eau douce 1836, 
that is, there can be distinguished in 
Nat. XIV. 1840, p. 222). Coste asserts the presence 
of a nervous system in Pennatula (Froriep’s neue 
Notizen, 1842, No. 450, p. 154), That which Spir 
ded to have discovered in the foot of Acti- 
p. 41, pl. I. fig. 2) in Lophopus er llinus (Plu- 
matella cristata of Lamarck); and by Coste 
(Comp. rend. XII. 1841, p. 724)in the Plumatellae 
in general. Nordmann also has seen a similar 
ganglion under the mouth of Plumatella campa- 
nulata (Lamarck) (loc cit. p. 709), and of Tendra 
zostericola (Aun. d. Sc. Nat. XI. 1838, p. 190). 
A ding to Van Beneden, a nervous ring sur- 
rounds the cesophagus of Adcyonedia (Ann. d. Sc. 
*[§ 33, note 1.] Allman has observed with 
Cristatella mucedo asmall roundish body situated 
at the upper end of the pharynx, and which he re- 
gards asa nervous ganglion (Rep. Brit. Assoc. Ad- 
vancem. of Sc. 1846, p. 88). This observation he 
subsequently confirmed, and has observed with 
Plumatella repens this ganglion ( which he terms 
the great oesophageal ganglion) send off a large 
filament to each of the tentaculiferous iobes ; also 
a smaller one passing off at each side to embrace 
the cesophagus, while a very short one was distrib- 
pr 
nia (Ann. d. Mus. d’Hist. Nat. 1809, p. 443, pl. 
XXXIII. fig. 4) has been properly rejected by 
most modern zootomists, as an illusion. See Ber- 
thold, loc. cit. p. 6.* 
1 Lovén, Wiegmann’s Arch. 1837, I. p. 323. 
2 Steenstrup, Ueber den Generationswechsel, p. 
uted In the substance of this last organ. And, 
finally, another set of filaments were distributed te 
the organs about the mouth. See Report of the 
same, for 1849, p. 72. According toa late Report, 
this observer appears to have been able to make 
out a distinct nervous system in all the fresh-wa- 
ter Bryozoa, except Paludicelia. He has, how- 
ever, been able to detect no certain organ of spe- 
cial sense. See report of the same for 1850, p. 
319.— Ep. 
