Rumen contents obtained from 30 domesticated cattle (Bos taurus L.), slaughtered at abattoirs in the vicinity of Izmir, were surveyed for ciliates belonging to the genus of Ophryoscolex. Results of this survey suggested that the ciliates in this two genus should not be classified to the species level on the basis of caudal spination characteristics or the number of the rings of secondary caudal spines, as previously proposed (1, 2). Populations intermediate in these characteristics were detected in Turkish cattle and analysis of the morphometrical data for all criteria did not indicate significant differences for establishing separate species. It appears that these features, which show continuous variation, are more appropriate for classification as formae. Therefore, this genus has been revised. O. purkynjei and O. caudatus, previously described as two different species, are now considered as the same species, O. purkynjei, according to the priority in Systematic Zoology. Three new formae (O. p. f. purkynjei n. f., O. p. f. bifidobicinctus n. f. and O. p. f. bifidoquadricinctus n. f.), all belonging to O. purkynjei are described and a new key proposed for identification (p. 28).

Rumen contents obtained from 30 domesticated cattle (Bos taurus L.), slaughtered at abattoirs in the vicinity of Izmir, were surveyed for ciliates belonging to the genus of Ophryoscolex. Results of this survey suggested that the ciliates in this two genus should not be classified to the species level on the basis of caudal spination characteristics or the number of the rings of secondary caudal spines, as previously proposed (1, 2). Populations intermediate in these characteristics were detected in Turkish cattle and analysis of the morphometrical data for all criteria did not indicate significant differences for establishing separate species. It appears that these features, which show continuous variation, are more appropriate for classification as formae. Therefore, this genus has been revised. O. purkynjei and O. caudatus, previously described as two different species, are now considered as the same species, O. purkynjei, according to the priority in Systematic Zoology. Three new formae (O. p. f. purkynjei n. f., O. p. f. bifidobicinctus n. f. and O. p. f. bifidoquadricinctus n. f.), all belonging to O. purkynjei are described and a new key proposed for identification (p. 28).