All organ systems of mesothelid spiders are revised and supplemented with new
information. This concerns particularly the eyes, which were studied by TKM
comparing the data with previous results. Based on ultrastructure,
histology and experimental observations a hypothesis on vision in heptathelid
spiders is proposed. The ultrastructure of the mesothelid tarsal organ and
the trichobothria is described for the first time. Both organs are equipped
with numerous sensory cells. The respiratory capabilitiy of mesothelids is
investigated and discussed in relation to mygalomorph and araneomorph spiders,
which represent the two major taxa of opisthothelid Araneae.
A special chapter is devoted to the morphology and function of the male palpal
organ which is compared to respective organs in mygalomorph and araneomorph
spiders. Its function is explained using morphological and experimental data.
Ecological aspects deal with the habitats of Mesothelae and especially
microbial diseases. In the chapter on taxonomy current problems concerning
mesothelid species are critically discussed from a general zoological