Developing protoscoleces of Echinococcus granulosus on the outer surface of the brood capsule, detected by scanning electron microscopy.

By means of scanning electron microscopy, stalked protrusions were observed arising from the outer surface of intact brood capsules of Echinococcus granulosus. Histological studies showed these protrusions to be developing protoscoleces. However, complete development is not attained and the protoscoleces eventually die. It is suggested that external development is a result of overcrowding within the brood capsule.