Yasumasa Tongu
School of Health Science, Okayama Unversity, Okayama 700, Japan.

Hidekazu Hata
Muneo Yokogawa
Department of Parasitology, Shool of Medicien, Chiba Unversity, Chiba 280, Japan.

Yasuhide Orido
Department of Public Health, Kyorin University School of Medicine, Mitaka City, Tokyo 181, Japan.

Mario Robert Pinto
Laboratorio de Helmintologia, Instituto de Biologia, Universidad Nacional Autonoma de Mexico, D. F. Mexico, Mexico

Rafael Ramothe Argumedo
Facultad de Ciencias Medicas, Universidad de San Carlos de Guatemala, Guatemala City, Guatemala.

Moriyasu Tsuji
Department of Parasitology, Kyorin University School of Medicine, Mitaka City, Tokyo 181, Japan.