Onychophora sentence example
Very usually (but not in the Onychophora = Peripatus) all the parapodia are plated with chitin secreted by the epidermis, and divided into a series of joints - giving the " arthropodous " or hinged character.
In Diplopoda (Julus, &c.) the results of embryological study point to a composition of the front part of the head exactly similar to that which we find in Onychophora.
It may be pointed out that the most radical difference presented in this list is that between appendages consisting of the corm alone without rami (Onychophora) and those with more or less developed rami (the rest of the Arthropoda).
The Arthropod eye appears to be an organ of special character developed in the common ancestor of the Euarthropoda, and distinct from the Chaetopod eye, which is found only in the Onychophora where the true Arthropod eye is absent.
We are also, by the isolation of Peripatus and the impossibility of tracing to it all other tracheate Arthropoda, or of regarding it as a degenerate offset from some one of the tracheate classes, forced to the conclusion that the tracheae of the Onychophora have been independently acquired.Advertisement
Peripatus, though indubitably an Arthropod, differs in such important respects from all the old-established Arthropod classes, that a special class, equivalent in rank to the others, and called Prototracheata or Onychophora, has had, as we have seen, to be created for its sole occupancy.
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).