NUMEROUS attempts to reproduce the malformations which occurred in human babies from ‘Thalidomide’-treated mothers have met with only limited success1–3. Although many representatives of aves and mammalian experimental species have been investigated for this purpose, the results fall short of paralleling the effect of the drug on the human foetus4. Sub-human primates have been utilized on two occasions5,6. Lucey and Behrmann5 showed that treating rhesus monkeys with ‘Thalidomide’ before implantation resulted in the inhibition of implantation. Delahunt and Lassen6 induced typically malformed foetuses in four of seven pregnant Cynomolgus monkeys which were treated after implantation had already occurred (days 32–42). Although the embryology of the baboon has not been investigated as extensively as that of some other sub-human primates, developmental processes paralleling those in the human have been found7. Further investigation of the embryology is in progress.