Note: They have four pairs of legs, no antennæ nor wings, a pair of mandibles, and one pair of maxillæ or palpi. The head is usually consolidated with the thorax. The respiration is either by trancheæ or by pulmonary sacs, or by both. The class includes three principal orders: Araneina, or spiders; Arthrogastra, including scorpions, etc.; and Acarina, or mites and ticks.
ARACHNIDAN
A*rach"ni*dan, n. Etym: [Gr. (Zoöl.)
Defn: One of the Arachnida.
ARACHNIDIAL Ar`ach*nid"i*al, a. (Zoöl.) (a) Of or pertaining to the Arachnida. (b) Pertaining to the arachnidium.
ARACHNIDIUM
Ar`ach*nid"i*um, n. Etym: [NL. See Arachnida.] (Zoöl.)
Defn: The glandular organ in which the material for the web of spiders is secreted.
ARACHNITIS
Ar`ach*ni"tis, n. Etym: [Gr. (Med.)
Defn: Inflammation of the arachnoid membrane.
ARACHNOID
A*rach"noid, a. Etym: [Gr.
1. Resembling a spider's web; cobweblike.