Two new species of Paramphtstomum from cattle are described, namely, P. hiberniae n.sp. and P. scotiae n.sp., first collected from Irish and Scottish cattle respectively.

A brief account of gametogenesis and early cleavage division is given.

The chromosome number for P. scotiae is n=8, 2n=16, for P. hiberniae no definite number is given but it is believed to be n = 8 (6–8), 2n=16 (12–16). Notes are made on some specimens received from the Netherlands and France.

P. hiberniae and P. scotiae are compared with P. cervi and P. leydeni.

The value of the hanging-drop technique as used by Professor Buckley for the examination of the different views of the tip of tail and head of small nematodes is stressed. The spicules of various species of Enterobius have been examined with polarized light and the significance of the basal portion of the spicules is discussed.

E. vermicularis is recorded for the first time from the Chimpanzee(Anthropopithecus troglodytes), the Lar Gibbon of Malaya (Hylobates lar) and the Silky or Lion Marmoset (Leontocebus rosalia) all of which had been in the London Zoological Gardens for varying periods.

The hitherto unķnown male of E. anthropopitheci is described and the female is redescribed.

A new species, E. buckleyi from the Orang Utan(Pongo pygmaeus) is described.

A new species, E. lerouxi from the Gorilla(Gorilla gorilla) is described. This is the first record of an Enterobius from this host.

E. bipapillatus is described and recorded for the first time from the Guenon Monkey(Cercopithecus aethiops) from S. Rhodesia.

A new species, E. brevicauda is described from the Chacma Baboon(Papio porcarius) from S. Rhodesia. This is the first record of an Enterobius from this host.

Negative findings for Enterobius are recorded from ten postmortem examinations and fourteen NIH swab examinations of Rhesus Monkeys(Macaca mulata).

A new species, E. interlabiata is described from the Feline Douroucouli(Aotus felinus) from S. America. This is the first record of an Enterobius from this host.

In view of the criticism of Kreis (1932) the type and paratype material of E. atelis, E. lagothricis and E. duplicidens and some more recent collection of E. lagothricis have been re-examined and the findings of Cameron (1929) and Buckley (1981) confirmed.