$ 306. 3TT 
THE ARACHNOIDAE. 
small animals can pierce or cut as may be required. These cheliceres are 
-free, or lodged in a sheath out of which they may be protruded; some- 
‘times they are covered, above or below, by a frontal or chin-like process. 
In a few instances, these processes are united, forming a proboscis out of 
which the cheliceres may be protruded.” The first pair of maxillae, 
which are inserted on the sides of the cheliceres, are wholly unfit for masti- 
eatory organs, and, being destined for tactile parts, they have the form of 
palpi. These palpi are sometimes multi-articulated, sometimes uni-articu- 
Jated, and, from their various modifications, have received the names of 
Palpi rapaces, anchorarii, fusiformes, filiformes, antenniformes, valvae- 
formes, and adnati. 
3. The Oribatea, which, from their herbivorous nature, hold a distinct 
piace, not only among the Acarina, but also among the Arachnoidae in gen- 
eral, are distinguished also for the organization of their buccal organs. 
Their cheliceres are protractile, and the first pair of maxillae, situated 
under them, forms a complete masticatory apparatus, their basilar article 
being developed at the expense of the rest into a large denticulated 
piece. The other articles form only a very short palpus. 
4, The Pycnogonidae, Opilionina, Pseudoscorpii, Galeodea, and Scor- 
pionidae, all, have tri-articulated cheliceres. Under these last are situated 
the first pair of maxillae which have no masticatory character.” With 
the Scorpionidae, and Pseudoscorpii, they are long-forficulate, while, with 
the Galeodea, the Pycnogonidae and Opilionina, they are antenniform. 
With the Phalangidae, only, there is observed on their basilar article, a 
hairy, obtuse appendage, comparable to a rudimentary maxilla.® With 
the Scorpionidae, the two basilar articles of the pincers are so approx- 
imated by their flattened internal surfaces, that they may well be used for 
the bruising of soft animal substances.” 
5. With the Phrynidae, and Araneae, the cheliceres have the form of 
bi-articulated, unciform antennae. The basilar article of these so-called 
mandibles is always very thick, and the terminal article consists of a 
small, very sharp hook. When at rest, this last lies folded on the inter- 
2 For the cheliceres of the Acarina, see the de- 
scriptions and figures of Hermann, Duges, and 
Dujardin, Moc. cit.). These organs are forficulate 
with the Acarea, Gamisea and Bdellea; see Du- 
jardin, Observ. au Microsc. Pl. XVII. fig. 10, 11 
«<Acarus). They are unguiculate with Trombidi- 
um, Erythraeus, Smaridia, Atax, and Eylais ; 
see T'reviranus, Verm. Schrift. I. Taf. V. fig. 29 
(Trombidium). They are styliform with the [x- 
odes, Tetranychus, Rhyncholophus, Rhaphig- 
nathus, and Hydrachna. The frontal prolonga- 
tion is regarded by some authors as an under lip. 
It is found with Dermanyssus and Rhaphigna- 
zhus ; while, vith Ixodes, it belongs to the chin, 
aud thus forms an under lip. With Smaridia, 
and Sarcoptes, the ch es are d by 
akind of tube; see Dujardin iia aa &e. Pl. 
XVII. fig. 1-4 (Sarcoptes). ith Invodes, the 
cheliceres are cultrate and denticulate on their 
external borders; see Savigny, Descript. de 
VPEgypte, Pl. IX. and Audouin, Ann. d. Sc. Nat. 
XXV. Pl. XIV. The brevity and inequality of 
these organs, as noticed by dudouin with Imodes 
erinacei, were due tothe circumstance that they 
were imperfectly and unequally protruded from 
their sheath. 
8 This classification of the palpi belongs to Du- 
ees ; see Ann. d. Sc. Nat. L. p. 11. 
32* 
41 have satisfied myself of the presence of 
horny denticulated maxillae, fitted for mastication, 
with Hoplophora, Pelops, Zetes, Oribates, Da- 
maeus, and with other Oribatea. 
5 Some Pycnogonidae form the only exception in 
this respect. With Pariboea, the cheliceres are 
simple, bi-articulate and clavate ; but with Endets, 
Pycnogonum, and Phoxichilus, they are wholly 
wanting ; see Philippi, in Wiegmann’s Arch. 
1843, I. Taf. IX. fig. 1-3; also Savigny, Johns- 
ton, and Milne Edwards, loc. cit. 
6 Savigny, Mem. &c. I. Pl. VI. fig. 2, d. 
7 It-is well known that the Scorpionidae and 
the other rapacious Arachnoidae, merely suck 
their prey ; but it is said that Galeodes devours 
completely the insects which it has caught, seizing 
them with their cheliceres, and eating them piece 
by piece. During these processes each chelicere 
acts separately (Hutton, Ann. of Nat. Hist. XI. 
1843, p. 81, or Froriep’s neue Not. XXVIII. p. 
49). The Phalangidae have probably the same 
habits, for fragments of insects which they have 
eaten are found in their digestive canal (Tu/k, 
loc. cit. p. 248). 
8 See Roesed, loc. cit. Taf. XXXVII.,and Sa- 
vigny, Descript. de Egypte, Pl. I.-VIIL, also Ly- 
onet, loc. cit. Pl. XIX. XXI. 
