Spencer), as in the Araneae and Opiliones, and, on the other hand, may terminate in simplification and degeneration, as in the Acari.
2nd) somite (Opiliones) of the opisthosoma, there being rarely an additional stigma on the 4th (some Solifugae).
The Opiliones seem to lead on from the Spiders to the Mites.
Apparently related to the Opiliones are two extinct groups, the Anthracomarti and Phalangiotarbi, which are not known to have survived the Carboniferous period.
I Opiliones; after Thorell.
Hansen and Sorensen, On Two Orders of Arachnida (Cambridge, 1904); Sorensen, " Opiliones laniatores," Nat.
Orders: Pedipalpi, A raneae, Palpigradi, Solifugae, Pseudoscorpiones, Podogona, Opiliones, Rhynchostomi (Acari).