/ . A. 



PREFACE 



A few consolidated sources of descriptions and illustrations of plant 

 and soil forms, in particular, are available and should be used along 

 with the taxonomic keys. At best, keys are only attempted short cuts 

 to" the recognition of certain specimens. In all cases check the deci- 

 sions by referral to descriptions and illustrations of the nematodes. 

 There are some excellent volumes available to workers who do not have 

 access to the necessarily large reprint files of the taxonomist. The 

 book by Filipjev & Stekhoven, 19i+l can still be purchased. The book 

 by T. Goodey, 195l is out of print, but can be found in some libraries; 

 so useful a book should be reprinted soon. Fortunately, two other works 

 that every nematologist should have are again available. These are the 

 monographs by Thorne and Swanger, 1936 (reprinted 1957) and Thorne, 1939 

 (reprinted 19^7 )« V/e have drawn heavily from all of these sources and 

 want to point out that keys are by no means a substitute for the infor- 

 mation contained in these soiorces. 



The book. Introduction to Nematology by Chitwood & Chitwood, is probably 

 bhe recognized standard work on morphology and will be of great help in 

 anderstanding the morphological terms used in the keys. Volume III of 

 the Invertebrate series by Hyman, 1951 may also be helpful in this re- 

 spect, but to a lesser extent. 



In utilizing the various sources of information available, a pattern 

 for the reference headings v/as used. Thus, if a new key was developed 

 by the authors, no reference to another source is given. If another 

 author's key was used directly with only minor changes, it is acknowl- 

 edged as being "from" that source. If key contains basically the same 

 information as another source, but with changes having been made in con- 

 tent, it is referred to as being "modified" from the original. If only 

 the form of a key is alteredj^ it is referred to as being "after" the 

 original source. In some cases material from other sources was used as 

 a part of a new key and this is acknowledged by the word "including" in 

 the reference heading. 



The form in which this syllabus is printed and assembled will enable each 

 owner to keep the information current with the steady outpouring of taxo- 

 nomic work. As revisions of particular groups become necessary, new pages 

 can be typed and inserted along with or instead of the old pages. Addi- 

 tional pages can be conveniently designated with alphabetical characters, 

 for example, 17a. This system will keep the page references intact, A 

 further suggestion to the user 3 insert labeled, tabbed diArLder sheets for 

 qiiicker finding of particular groups. 



The plan was to provide through this set of keys a foundation on which 

 each person could continue to build and thus maintain a useful working 

 tool. 



