160 
With the Dorsibranchiati, the many delicate threads which arise from 
the cerebral ganglion by special roots and pass to the different portions of 
the digestive canal with a ganglion here and there upon their course, -may 
be regarded as splanchnic nerves. 
With the Amphinomae, Euniceae, Nereideae and Ariciae, there arise 
from the posterior border of the cerebral ganglion two roots which may be 
regarded as Nervt pharynget superiores, and which unite near their origin 
into a Ganglion pharyngeum superius. From this last pass off posteriorly 
delicate threads which form many ganglia upon the esophagus, and after- 
wards spread over probably many other parts of the digestive canal. 
Beside this Plexus splanchnicus superior, there is sometimes a Plerus: 
splanchnicus inferior —formed by other roots which pass off inferiorly 
from the brain; part of these form under the cesophagus a Ganglion pha-. 
ryngeum inferius, while others, passing backwards, constitute Nervi pha- 
ryngei and esophagei. ; 
The Amphinomae have on each side of the abdomen a very remarkable 
ganglionic chain. Their ganglia intercommunicate, not only by longitudinal, 
but also by transverse anastomoses, with the central mass of the nervous 
system. Among these last, those which are given off from the anterior 
lateral ganglia, join the connecting filaments of the esophageal ring; while: 
the others, arising from the posterior lateral ganglia, go to the various 
THE ANNELIDES. $ 149. 
ganglionic enlargements of the ventral cord.@? 
It has not yet been possible to ascertain the signification of these lateral 
ganglionic chains. 
CHAPTER IV. 
ORGANS OF SENSE. 
I. Organs of Touch. 
§ 149. 
With the Annelides, the sense of touch is particularly developed at the 
cephalic extremity. 
15 Cuvier (Leg. d’Anat. Comp. IT. 337) has no- 
ticed with Aphrodite two nerves passing back- 
wards which ought to be regarded as of a splanch- 
nic nature; but Grube’ (Zur. Anat. d. Kiemen- 
wiirmer, p. 58) has been unable to find them even 
in th@®same species. 
16 Stannius (Isis, 1831, p. 986, Taf. VI. fig. 8, r. 
r.), and Grube (De Pleione carunculata, 1837, p 9, 
fig. 5, r.), have seen with certain speeies of Amphi- 
nome the two roots of the Plexus splanchnicus 
superior, but were unable to trace them further. 
However, with Eunice Harassii, Grube (Zur. 
Anat. d. Kiemenwiirmer, p. 43, Taf. II. fig. 9, i.) has 
found beside these two roots, the Ganglion pharyn- _ 
geum superius which they form, and the nervous 
filaments which pass off from this last. Quite lately, 
Quatrefages has given very exact and detailed 
descriptions and figures of the expansions of the 
Plexus splanchnicus superior and inferior, with 
Eunice Nereis, Glycera, Phyllodoce, and Arici- 
nella ; see Ann. d. Sc. Nat. 1844, II. p. 81, Pl.1. I. 
With some Lumbricini, this extremity is prolonged 
into a kind of tentacular proboscis. 
The Branchiati have special and. 
17 These two ganglionic chains were first de~ 
scribed by Stannius with Amphinome rostrata 
(Isis, 1831, p. 986, Taf. VI. fig. 4). He saw three 
ganglia connect with the cesophageal ring on each 
side. But Grube (De Pleione carunculata, p. 10, 
fig. 5) has seen six on each side with Amphinome 
carunculata. These lateral ganglia, moreover, 
remind one of those described by Wagner, as al- 
ready noticed with Pontobdella muricata. 
1 According to Rathké (Danzig. Schrift. loc. cit. 
p. 94, 100), the two cephalic and respiratory fossae- 
with the Nemertini, are the seat of a most delicate 
sense of touch ; and their white, long and protrac- 
tile proboscis is also a tactile organ. But other 
naturalists attribute wholly different functions to 
these organs. 
2 The proboscis is non-articulated with Wats pro- 
boscidea, and Euanes filiformis (Grube, Wieg- 
mann’s Arch. 1844, I. p. 204, Taf. VII. fig. 1). 
But it is articulated with Rhynchelmis (Hof. 
meister, Ibid. 1843, I. p. 192, Taf. IX. fig. 8). 
