Abstract:To observe the ultrastructures of adult worms and eggs of Armillifer agkistrodontis by scanning and transmission electron microscope.Adults and eggs of Armillifer agkistrodontis were embedded in epoxy resin after cleaning,fixing,drying,and treatmeut with sputtering gold.The material was cut into thin sections with a LKB-E super slicer,double stained and viewed in S-520 scanning electron microscope and Philp CM210 transmission electron microscope.There were 6-9 abdominal annuli of adult A.agkistrodontis in scanning electron microscope,and waved folds were seen between the abdominal annuli of the body surface.There was a pair of curved hamuli on both sides of the mouth,while small spines like mastoid process were covered with the shape of the body.Scattered,raised oval pore-like sense organ was only seen on the both sides of the front and the end of the adult A.agkistrodontis.Anal pore and genitalia were seen at the abdominal end.There were three cortical layers of adult A.agkistrodontis in transmission electron microscope,they were outer cortex,inner cortex and base plate(membrane).Eggs of A.agkistrodontis were oval in transmission electron microscope,and they had a frame of three layers,outer membrane,transparent layer and medullary layer.Small spines like mastoid process covered with the shape of the adult A.agkistrodontis,scattered sense organ was only seen on both sides in the front and the end of the body,while it was different from larval of A.agkistrodontis whose sense organ was covered with the body.There were three cortical layers of adult A.agkistrodontis in transmission electron microscope,they were outer cortex,inner cortex and base plate(membrane),which was different from the six-layer frame of larval of A.agkistrodontis.Eggs in the ovary were obviously different from vitro eggs in scanning and transmission electron microscope.