2 9 6 THE NA TURE-STUD Y REIVE IV ■ [a . g _ UEC ., igo6 



THE KEEPING AND REARING OF CRAYFISH FOR CLASS USE 



BY E. A. ANDREWS 

 Associate Professor of Biology in Johns Hopkins University 



[Editorial Note. — Dr. Andrews has for many years been making an inter- 

 esting series of studies of crayfishes kept in his laboratory. Some of his recent 

 articles in scientific journals suggested to the managing editor of The Review 

 that the methods of keeping crayfishes alive in perfectly healthy condition ought 

 to be widely known; and so Dr. Andrews was urged to write some notes on his 

 experiments. The following article contains many practical suggestions for 

 elementary schools, many more for high schools, and every line is useful for col- 

 lege. In fact the article is one of the many already published which establish the 

 claim that The Nature-Study Review is "devoted to all phases of nature-study 

 in schools," — not simply for elementary schools as originally planned, but for all 

 schools in which it is desirable to give pupils and students some personal acquaint- 

 ance with the common natural things considered independently of scientific organ- 

 ization] 



Thanks to its standing high in the great phylum, Arthropoda, and 

 to its size, neatness, world-wide distrihution and ease of getting, the 

 crayfish scarcely needed the advertisement given by Professor Hux- 

 ley's classic book to place it in the first rank of animals that find favor 

 in the eyes of the teacher of zoology. In fact the crayfish amongst 

 non-vertebrates plays much the same part as the frog amongst verte- 

 brates in teaching our ideas of morphology. 



Since crayfishes are so extensively used by the angler as bait and 

 by the epicure as garnish and as food, they are generally easily 

 obtained in the markets and it is scarcely necessary to keep them long 

 in the school if they are to be used merely for brief anatomical stud- 

 ies. But when more than this morphological study is the aim it is 

 important to know how to keep the creatures alive, and the follow- 

 ing suggestions may prove of value. 



These suggestions result from observations made in the climate of 

 Baltimore, Md., upon the common crayfish, Cambarus affinis, C. 

 Clarkii, C. immunis, C. Diogenes and C. Bartoni; and with some 

 change they should be applicable to all American species of crayfish. 



To the teacher without experience with these animals the chief pit- 

 fall is, perhaps, the idea that crayfish must have deep water, whereas 

 the first essential is air and not water. Left in deep water the 



