$§ 302. THE ARACHNOIDAE. 373 
§ 302. 
A Splanchnic nervous system has been observed with only the higher 
Arachnoidae ; but here it is highly-developed. The odd stomachic nerve 
has been the part most difficult to discover; it is observed, however, with 
some Araneae, — the posterior border of the brain sending off two small 
filaments which traverse the central opening of the stomach but unite on 
its dorsal surface.” The Scorpionidae have a similar stomachic nerve which 
also arises from the brain by two filaments which have a small ganglion at 
the point of their union.® 
With the Phalangidae, Araneae, Galeodea, and Phrynidae, the splanch- 
nic nerves are very distinct. They arise from the posterior border of the 
ventral nervous mass situated in the cephalothorax, and are distributed to 
the digestive, respiratory, circulatory, and genital organs, and have, some- 
times, ganglia on their course. With Phalangium, there are three of 
these nerves arising from the posterior border of the transverse portion of 
the ventral mass. The middle one of these nerves divides into two 
branches, which dilate into two ganglia connected together by a transverse 
anastomosis. From these two ganglia arises a nervous plexus, which is dis- 
tributed to the internal genital organs, and to the corium. The lateral 
nerves, directly after their origin, likewise divide into two branches, each of 
which forms a ganglion; the external nerves after a shorter, and the inter- 
nal after a longer course. The two external ganglia thus formed send fila- 
ments to the terminal portion of the genital organs, while those of the two 
internal ganglia are distributed to the digestive tube and neighboring or- 
gans.© With the Araneae, the Galeodea, and Phrynidae, the posterior 
extremity of the principal ventral ganglion sends off two considerable 
nervous cords, contiguous, which pass into the abdominal cavity where they 
are distributed, radiatingly, to the digestive organs, to the pulmonary sacs, 
to the genital organs, and to other abdominal viscera. Sometimes, before 
dividing, they unite in a common ganglion. : 
1 This Nervus sympathicus recurrens was dis- 
covered by Brandt, with Epeira ; see Mediz. Zool. 
IL. p. 90, Taf. XV. fig. 4, d., and fig. 6,c., or in 
the Isis, 1831, p. 1105, Taf. VIL. fig. 6, b., and Be- 
merk. tib, d. Mundmagennerven, loc. cit. p. 15, or 
Aun. d. Sc, Nat. V. p. 94, and XIII. p. 185, Pl. 
IV. fig. 2,c. This same nerve has been refound by 
Grube (loc. cit. p. 302), with other indigenous 
Araneae. With Mygale, according to Dugés (Ann. 
d. Sc. Nat. VI. p. 175), there are, instead of two 
simple fil , two lateral ganglionic net-works, 
from the brain to the stomach. 
2 See Newport, loc. cit.* 
8 Sce Treviranus, Verm. Schrift. I. p. 38, Taf. 
ae Ss. 24, and T'ulk, loc. cit. p. 325, Pl. V. fig. 
1 33. 
4 This ganglion has been observed by T’revira- 
nus (Bau d. Arach. p. 45, Taf. V. fig. 45), with the 
indigenous Araneae, and by Duges (Ann. d. 8c. 
Nat. VI. p. 175), with Mygale. According to 
Brandt (Mediz. Zool. II. Taf. XV. fig. 3, and 
Ann. d. Sc. Nat. XIII. p. 186, Pl. IV. fig. 4), this 
ganglion is wanting with Epeira, and Trevi- 
ranus (Zeitsch. f. Physiol. IV. p. 95), has vainly 
sought for it in a Brazilian spider. Blanchard 
(loc, cit. p. 1384), has found it with Galeodes, and 
Van der Hoeven (Tijdsch. X. p, 370), with Thely- 
phonus. 
* (§ 302, note 2.] See also Dufour, loc. cit. p. 251. —Ep. 
