Abstract
The karyotypes of the two amphistomes Calicophoron microbothrium Fischoeder, 1901 and Carmyerius gregarius (Looss, 1896), Stiles & Goldberger, 1910 from Egyptian ruminants were studied using the air drying technique. The two species have similar number of chromosomes (n = 9), but differ in chromosome morphology. All the chromosomes of C. microbothrium are subtelocentric, except the first and the fifth are metacentric, whereas the chromosomes of C. gregarius are submetacentric, subtelocentric and acrocentric. Some cells in the two species showed tetraploidy. The results are discussed in terms of the phylogenetic relationship of different amphistomes.