Taxa included

Firstman, B. (1973). The relationship of the chelicerate arterial system to the evolution of the endosternite. Journal of Arachnology 1: 1–54.

Taxon
Anchigarypus californicus (Banks, 1909) (Pseudoscorpiones: Garypidae) 5, 16, fig. 10, Garypus californicus
Pseudocellus boneti (Bolívar y Pieltain, 1942) (Ricinulei: Ricinoididae) 5, 18, figs 11a–b, Cryptocellus boneti
Pseudocellus osorioi (Bolívar y Pieltain, 1946) (Ricinulei: Ricinoididae) 5, 18, Cryptocellus osorioi
Hubbardia pentapeltis Cook, 1899 (Schizomida: Hubbardiidae) 5, 24, fig. 17, Trithyreus pentapeltis (Cook)
Mastigoproctus giganteus (Lucas, 1835) (Uropygi: Thelyphonidae) 5, 22–23, figs 14–15, Mastigoproctus giganteus (Lucas)
Prokoenenia wheeleri (Rucker, 1901) (Palpigradi: Prokoeneniidae) 5, 6–8, fig. 3, Prokoenenia wheeleri (Rucker)