THE AMERICAN NATURALIST [Vol. XL VI 



gills, while those of the genus Cambarus have but seven- 

 teen. The female of the genus Cambants has a false 

 pouch, the annulus ventralis, which serves as a sperm re- 

 ceptable, while in Astacus the sperm is deposited on the 

 posterior part of the thorax in spermatophores. 



Dr. A. E. Ortmann has made most careful studies of 

 the distribution of the crayfish. References to his papers 

 will be found in my bibliography. Dr. Ortmann writes 

 me that there are in the United States and Central Amer- 

 ica, 74 species of Cambarus and 5 of Potambius (Asta- 

 cus). In the United States excluding Mexico, Guatemala 

 and Cuba, there are 64 species of Cambarus and 5 of 

 Potambius. 



The European word "crayfish" is used by teachers of 

 zoology, probably because of Huxley's classic, "The 

 Crayfish." 



Ortmann found (38) that not only was "crawfish" 

 used by Say, 1817, earlier than "crayfish" by Huxley, 

 1880, but that in this country "crawfish" is the popular 

 name. 



"Crayfish," "crawfish," or, as it is sometimes incor- 

 rectly called, "crab," come from the same root, Old Ger- 

 man, ' ' Krebis, ' ' from which are derived, on the one hand, 

 the modern German " Krebs " and the English " crab "; 

 on the other hand the French " ecrevisse," the English 

 and the American " crayfish." 



The crayfish on which my own observations have been 

 centered belong to the species Cambarus Jxirtonius bar- 

 toni, the only species which has migrated into New Eng- 

 land. 



My work was carried on in the field and in the labora- 

 tory continuously for nine months. In the field I have 

 watched the activities of the crayfish in the small ponds 

 with which Worcester, Mass., is so well supplied. At 

 night I used a powerful acetylene gas lamp. In the lab- 

 oratory I made use of two large aquaria, one of them an 

 ordinary running water aquarium with a pile of sand at 



