should thus call the cautious conclusions of the author, can be formulated 

 approximately as follows: Each order of birds is characterized by its 

 special tapeworm fauna and as a rule the separate species of the latter 

 are encountered only on a determined order of birds or even adapted to 

 their smaller groupings of classification. The formulation of the "rule of 

 Fuhrmann" in the interpretation of K. I. Scriabin, N. J. Ass, and G. S. 

 Markov is as follows: Each order of birds with a few exceptions is 

 characterized by a specific helminothofauna, the representatives of which 

 cannot parasitize the birds of other orders. 



By comparing both formulations we see that in the first place 

 Fuhrmann spoke only about the tapeworm fauna and that the helminothofauna 

 in general was later added to his rule. In the second place he writes that 

 as a rule separate species of tapeworms are encountered only in a de- 

 termined order of birds, whereas in the text of Scriabin-Ass -Markov there 

 is an indication that "the representatives of the helminothofauna cannot 

 (the italics are ours--BB) parasitize etc. " The categoric attitude of the 

 last expression bears a completely different character than the definitions 

 of the text of Fuhrmann. 



Thus, in its initial form "the rule of Fuhrmann" does not 

 correspond to what is passed as his and the author is not responsible in p. 295 



any way for what others have represented as his "rule. " Let us note also 

 that to Fuhrmann are ascribed completely unexpected things. Thus, in 

 the work of A. G. Knorre (1937) "the rule of Fuhrmann" is expressed 

 thus: "related parasites in related hosts. " Meanwhile if one should 

 examine attentively what Fuhrmann wrqte.one will see that this is not at 

 all what he said because the statement quoted by us allows us to consider 

 with certainty that he allowed the possibility of the presence, in different 

 orders of birds, of very close and even almost indistinguishable species, 

 i.e. , that related parasites can occur or be in unrelated hosts. This is 

 seen in any example of his work. Thus, close species of tapeworm from 

 the genus Echinocotyle are encountered in Anseriformes, Charadrii- 

 formes and passerines, that is on completely unrelated birds. There is a 

 large number of examples of such nature in the book of Fuhrmann. 



One can only regret that erroneous representations about "the 

 rule of Fuhrmann" are scattered in our literature. 



Let us now examine nnore attentively what "the rule of 

 Fuhrmann" represents, how normal (regular, nobis) it is, and whether it 

 can be applied to other groups of parasites in addition to tapeworms. 



Properly speaking "the rule of Fuhrmann" underscores only 

 the fact that the occurrence of separate species of bird tapeworms is 

 usually limited to a determined, sufficiently wide circle of hosts --an 

 order of the latter. In his resume'^of 1932 are cited materials on all the 



340 



