Lamarck included the Thysanura and the Myriapoda in his class Arachnida.
Specimens were subsequently obtained from other parts of the neotropical region, and from South Africa and Australia, and the animal was variously assigned by the zoologists of the day to the Annelida and Myriapoda.
These three authors definitely separated the Arachnida, Crustacea and Myriapoda as classes distinct from the Insecta (see Hexapoda).
This class has been named the Prototracheata or Onychophora (see Arthropoda), and may be most appropriately placed in the system in the neighbourhood of the Myriapoda, though it must not be forgotten that it differs from the Myriapoda more than the Myriapoda differ from other Arthropoda, and that in some respects it presents features which recall the segmented worms (Annelida).
Ray's "Insects" comprised the Arachnids, Crustacea, Myriapoda and Annelida, in addition to the Hexapods.