OBSERVATIONS ON OOPERIPATELLUS-DECORATUS, AN OVIPAROUS ONYCHOPHORAN FROM TASMANIA (ONYCHOPHORA, PERIPATOPSIDAE)

Characteristics of external morphology as well as internal anatomical and ontogenetical features of Ooperipatellus decoratus (Baehr, 1977) w ere studied with morphological and histological methods. The pattern o f six raised longitudinal rows of papillae on the dorsal instrument of this onychophoran is species-specific, while the colour of the integu ment varies within this species. Genital tracts of both sexes were exa mined and compared to those of other onychophoran species. A new dista l spermatophore-structure is described here, the function of which is yet unknown. The genital tract of adult females lacks receptacula semi nis but they are found in juvenile females. The number of eggs in the uteri of O. decoratus is variable (1-19), as in other oviparous onycho phoran species. The chorion of the eggs from O. decoratus shows a char acteristic pattern of starlike elements. One of the cultured females l aid up to 37 eggs in about two months. Under laboratory conditions egg s are laid throughout the year. A time period of seven months from fin ding an egg in the substrate to an attempted hatching could be documen ted. However, depending on the maturity of the egg at deposition, whic h is very variable, the developmental time can be shorter or longer. S ome observations on the development of living onychophoran eggs are de scribed. The attempted hatching of a juvenile onychophoran is document ed for the first time.