ISOTRICHA-JALALUDINII N-SP FOUND FROM THE RUMEN OF LESSER MOUSE DEER,TRAGULUS-JAVANICUS, IN MALAYSIA

Isotricha jalaludinii n. sp. found in the rumen of lesser mouse deer, Tragulus javanicus, in Malaysia was described and illustrated. This ne w species is characterized by the location and direction of the vestib ulum, shape of the macronucleus, and absence of a dent at the vestibul ar opening. The presence of single peculiar isotrichid species in the rumen of mouse deer, which is recognized as one of the most primitive ruminants, suggests that the isotrichid ciliates similar to I. jalalud inii and Isotricha intestinalis were established at a fairly early per iod during the evolution of ruminants.