MONIEZIA, A GENUS OF CESTODE WORMS AND THE 

 PROPOSED REDUCTION OF ITS SPECIES TO THREE 



By E. Leonard Taylor 



Of the Veterinary Laboratory of the British Ministry of Agriculture and 



Fisheries 



The work on which this paper is based was done in the laboratory 

 of the Zoological Division of the Bureau of Animal Industry, United 

 States Department of Agriculture, at the suggestion of Dr. Maurice C. 

 Hall. The material and facilities of the helminthological collection 

 of the United States National Museiun were put at the disposal of 

 the writer for this work. 



The question of the number of valid species in the genus Moniezia 

 was taken up by G. Theiler (in 1924) at the Liverpool School of 

 Tropical Medicine. She found a wide range of variation in the seg- 

 ments of a single strobila, and came to the conclusion that only four 

 species could be allowed, namely, M. expaiisa^ M. trigonophora^ M. 

 henedeni, and M. alba, and of these four she expresses a doubt as to the 

 validity of the two species M. tHgono'p'hora and M. alba. Two other 

 species, M. rugosa and M. amphibia, are placed as species inquirendae, 

 pending a reexamination of the original material. As this genus is 

 of considerable economic importance it seemed particularly desirable 

 to check over the above work. 



It is much easier to divide a group of individuals into a number of 

 species according to their various dissimilarities than to show satis- 

 factorily that a number of dissimilar individuals really belong to one 

 and the same species, and that their variations are not of specific rank. 

 And it is indeed impossible, from a mere morphological study, to 

 prove beyond doubt that the variations occurring do not go beyond 

 the limits of one species. Proof could only be found by studying the 

 variations occurring in the progeny of one parent worm, but our com- 

 plete ignorance of the life cycle of worms of the genus Moniezia un- 

 fortunately renders this impossible. 



The method followed in collecting data for this paper has been the 

 same as that used by G. Theiler ; fresh worms have been taken from 

 sheep and cattle at the abattoirs, and complete specimens stained and 



No. 2754.— Proceedings U. S. National Museum, Vol. 74. Art. 9 



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