A KEY TO THE GENERA OF FREE-LIVING NEMAS 



BY N. A. COBB 



Division of Nematology, U. S. Bureau of Plant Industry 



Checked, revised and prepared for the press by Margaret V. Cobb and Corinne Cooper 



CONTRIBUTIONS TO A SCIENCE OF NEMATOLOGY XXVI 1 



PREFACE 



This key, which was built up and used by N. A. Cobb as a card 

 catalog during forty years of work in nematology, had been reorgan- 

 ized in rough manuscript form during the last two years of his life. 

 As Miss Cooper and I had previously worked with him on this draft, 

 it seemed best for us to carry it to completion. In essentials and 

 in general form it is his key, but we are responsible both for cor- 

 rectness of detail (an appreciable amount of the detailed work was 

 incomplete, in need of revision, or in need of change because of ad- 

 dition or omission of genera), and for such decisions as have to be 

 made in getting such a work printed. Our aim has been to follow his 

 ideas wherever they were known to us, or where we could infer them, 

 and to make as few changes as possible in his outline. Nearly a 

 hundred entries have been omitted, chiefly his own new genera 

 which it has not been possible to publish in advance of publication 

 of the key. In some cases genera have been dropped as not being 

 free-living. Index, glossary and list of abbreviations have been added. 

 The bibliography has been prepared by Mrs. Rowena R. LeHew 

 of the Division of Nematology. The definitions in the glossary 

 are not intended to settle the meaning of terms for other workers 

 in the field, but merely to indicate the terminology used in this key. 



A few details in the form of the key stand in need of special explana- 

 tion. Parentheses have been used around generic names in the key 

 in two ways ; one, to indicate that the genus is better placed elsewhere 

 in the key, and two, with an equality sign, to indicate a synonym for 

 the accepted name of a genus. An example of this second use is given 

 by the first genus entry in the key. The symbols 9 for female, d" for 



Received September 20, 1934. 



1 Reprinted from the Proceedings of the Helminthological Society of Washington, 

 Vol. II, No. 1, January, 1935. Repaged without material alterations. 



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