380 $ 3808. 
THE ARACHNOIDAE. 
tube, of nearly equal size throughout, without a stomachic dilatation and 
without caeca, which opens by an anus at the posterior extremity of the 
body.” 
§ 308. 
The Salivary glands exist with, perhaps, all the Arachnoidae; for, they 
are found even in many of the lower forms, where their presence would be 
least expected. With the Tardigrada, there are on each side of the suck- 
ing apparatus, large, lobulated glandular tubes,"which appear to be organs 
of this nature, although their outlets have not yet been distinctly traced.” 
With the Oribatea, there is at the anterior extremity of the body, a pair 
of similar tubes, but simple and colorless, which extend to the mouth, 
and have undoubtedly a salivary function.® 
With Izodes, these organs are extraordinarily developed, consisting of 
two large masses of vesicles situated on the sides of the anterior part of the 
body, and opening by short ducts into two multiramose excretory canals. 
These last, whose walls are traversed by a solid spiral filament, open into 
the buccal cavity at the base of the lip-like process.® 
With the Araneae, a slit in the upper lip leads into a cavity situated 
above the palate, and at the base of this cavity is a transparent, glandular 
mass, which, very probably, secretes the saliva; this flows up through the 
slit in question, and moistens the substances from which the animal ex- 
tracts its food. As salivary organs should also be considered the two 
pairs of glandular tubes, which, with the Scorpionidae, are situated on the 
sides of the anterior part of the body, and extend forwards to open into 
the cesophagus. © 
With the Araneae, and Scorpionidae, there is a Liver distinct from the 
digestive tube, which, for a long time was regarded as an adipose mass. 
With the Tardigrada, Acarina, Pycnogonidae, and Opilionina, the walls of 
the stomachic appendages are of this nature, for they are glandular and com- 
posed of granular and usually yellowish-brown cells.” With the Araneae, 
the brown or dirty-yellow liver is very voluminous, filling a large portion 
of the abdominal cavity, and enveloping most of the other viscera. 
At first sight, it appears to be a compact mass, but, further examined, 
it is found composed of numerous multiramose, closely-aggregated caeca. 
The walls of these are thick, and crowded with hepatic cells, and they open 
into the digestive canal near its middle by four ‘short hepatic ducts. 
9 With the Scorpi , the anus is si d on 5 See Miller, loc. cit. p. 52, and Newport, 
the penultimate caudal segment. 
1 See Doyere, loc. cit. p. 321, Pl. XIII.-XV. 
2 I have seen these glandular tubes with Hoplo- 
phora, Zetes, and Oribates. 
3 The salivary glands of Iwodes ricinus resem- 
ble exactly the botryoidal ones of many of the In- 
secta, 
The secretory vesicles of the saliva are filled with 
transparent nucleated cells and surrounded by 
numerous ramified. tracheae with which it is im- 
possible to confound the excretory ducts of these 
glands; for with these last the spiral turns of thin 
filament are very wide apart, while, in the tracheae, 
the spiral windings are very close together. 
4This glandular apparatus has been seen by 
Wasmann (loc. cit. p. 8, fig. 16) with Mygale ; 
I have found it also with other Araneae, 
Philosoph. Trans. 1843, Pl. XV. fig. 39. 
6 With the Tardigrada, Acarina, and Opilionina, 
at least, I have seen, distinctly, hepatic cells in 
the walls of the stomachic appendages. See also 
Doyere, loc. cit. p. 327, Pl. XV. 
7 Treviranus (Bau d. Arachnid. p. 30, 47, Taf. 
II. fig. 24, dd., and Taf. V. fig. 47) had already 
observed the communication between the liver and 
the digestive organs. The remaining points in the 
structure of this organ have been rightly estimated 
by Duges (Ann. d. Sc. Nat. VI. p. 179), Grube 
(loc. cit. p. 299), and Wasmann (loc. cit. p. 18, fig. 
17, m. n., 20-22). See also Owen, Lectures, &c., 
p. 258, fig. 110, i. i. 
