Morphometric estimates of the surface areas of the tracheal and cuticular systems in Peripatus acacioi marcus and marcus (Onychophora).

The surface areas of the tracheal and cuticular systems of Peripatus acacioi individuals of different body weights were determined by morphometric analysis. The results demonstrate that both surfaces increase with body weight, although the observed increase in the surface area of the tracheal system appears to be at a greater rate. The slopes of the two regression lines obtained are statistically different. It is therefore suggested that the preferential route for water loss in P. acacioi is related to the size of the animals, i.e., smaller onychophorans would lose water mainly through the cuticle, while larger ones would lose water through the respiratory surfaces.