Syphacia obvelata, Syphacia muris and Aspiculuris tetraptera were recovered differentialy from the Nile
rat 'Arvicanthis niloticus', the brown rat 'Rattus norvigicus', the black house rat 'Rattus rattus', the house mouse 'Mus
musculus', the lesser short tailed gerbil 'Dipodillus simony', the laboratory rat 'Rattus norvigicus alba', and the
laboratory mouse 'Mus musculus alba' from different geographical localities in Egypt. The lesser short tailed gerbil
was recorded as new host record. Morphometric comparison between adults recovered from different hosts revealed
statistically significant variations in few structures. Scanning electron, as well as, light microscopy added to the
taxonomic valid characteristics that differentiate between the encountered oxyurids. These variations include: the
shape and surface structure of the lips and labial papillae; the occurrence of cephalic vesicles in both S. obvelata and
A. tetraptera but not in S. muris; the cervical alae being prominent in male S. obvelata but absent in females, present
in female S. muris but absent in males and present in both sexes of A. tetraptera; the caudal alae found in A.
tetraptera and absent in Syphacia spp.; spicules and gubernaculum present in both species of Syphacia, but not in A.
tetraptera; the number of transverse striae on mamelons varied in the reported Syphacia spp.; the shape of vulva
varied in the three encountered species. The structure of buccal cavity and oesophagus was defined and new criteria
were added. The number, shape and size of caudal papillae in males were recorded. Variations in the shape of the
transverse cuticular annulations in both sexes of the three encountered species were discussed. Results were
discussed in relation to previous reports.