Body consisting of three principal segments.
Mouth perfect, or rostellate[1239].
Antennæ distinct.
Legs six, in every state.
Octopods. This suborder consists of the Trachean Arachnida of Latreille, excluding the Pycnogonida; of the Acaridea, Sironidea, Phalangidea, and part of the Scorpionidea of Mr. MacLeay, and, with some exceptions, of the Linnean genera Acarus and Phalangium. This last tribe (for with Linné, I include Chelifer and Obsidium in the Phalangidea,) on one side approaches Scorpio by Thelyphonus, and on the other the Aranidea by Gonyleptes; or, according to Mr. MacLeay, the transit is to both by Galeodes[1240]. But as there is reason for thinking that this last belongs to the Pulmonary Arachnida[1241], and forms a peculiar type in that Class, I consider the transit from the one to the other as above stated. The folded abdomen of Gonyleptes seems much to correspond with that of the cancriform spiders (Carkinodes cancriformis, &c.).
Def. Metamorphosis complete.
Body consisting of one or two principal segments.
Mouth various[1242].
Antennæ obsolete, or represented by mandibles.
Legs mostly eight, but in a few six only[1243].