Scanning Electron Microscopy Of The Egg And The Second Stage Larva Of Toxocara Vitulorum

Abstract

The surface topography of the egg and 2nd stage larvae of the nematode Toxocara vitulorum are described by scanning electron microscopy. The eggs are oval and their surfaces are characterized by the presence of distinct ornamentations in the form of interconnecting ridges and shallow invaginations. The larvae have small cylindrical bodies with rather pointed extremities. The mouth opening is terminal and rounded or triangular in shape and is surrounded by six large ill-defined lips. Two prominent lateral alae are found slightly posterior to the cephalic end of the larva. Two large amphidial pores are found on the lateral sides of the mouth opening. The excretory pore is a large rounded opening on the ventral surface of the body. The cuticular surface of the larva is ornamented with ill-defined transverse striations. The anal opening is triangular and located subterminally on the ventral surface of the posterior extremity of the body.