Patent Office which are pertinent to the subject of this report. This 

 list is the product of an investigation conducted by the legal firm re- 

 tained by Cook Research Laboratories, Inc., Chicago, Illinois, while 

 under contract to the Fish and Wildlife Service. Presumably 

 it records, among the several arts included, the most significant pat- 

 ents granted for "fish screens" and similar devices through the calen- 

 dar year 1950 . A subsequent search indicated that no further patents 

 of this type were granted at least through 155>2. 



Nearly all of the citations presented have been checked for accur- 

 acy by comparison with the original articles or with suitable reproduc- 

 tions (photostats, microfilms, ....); five papers for which originals 

 could not be located were checked against typewritten "record" copies. 

 Those citations not verified by one of the two procedures are identified 

 by an asterisk (*). Transliterations and translations of citations in 

 Russian and Japanese have been verified by experts in those languages. 



Several inconsistencies that will be apparent in the method of ci- 

 tation have been introduced to facilitate the location of the periodicals 

 involved. City of publication is not usually given. It is included, 

 however, for those foreign journals that are entered in the catalogs of 

 certain libraries under place of publication. For some trade journals 

 and non-technical publications, the date of the particular issue cited 

 is given since that information is frequently more helpful than a know- 

 ledge of volume and issue number. 



Following citations, references are given to known abstracts, 

 summaries, reviews, reprintings, and available translations. Most 

 summaries, reviews, and reprintings indicated in these annotations are 

 not cited elsewhere in the body of the bibliography. Abstract systems 

 referred to are as follows: 



(1) Biological Abstracts, University of Pennsylvania, Phila., Pa. 



(2) Commercial Fisheries Abstracts, U. S. Dept. of the Interior, 



Fish and Wildlife Service, Washington, D. C. 



(3) World Fisheries Abstracts, Food and Agriculture Organization 



of the United Nations, Rome, Italy. 



Desirable as it might be to subdivide this bibliography into sec- 

 tions under various subjects, that procedure proved impractical. Many 

 of the references deal with a considerable diversity of subject matter. 

 Any attempt at subdivision accordingly would entail an unreasonable 

 amount of repetition or cross-referencing. 



