June 20, 190G.] 



SCIENCE. 



985 



mature and lay eggs the following spring 

 when not quite one year old, and also that a 

 female may lay eggs in two successive years. 

 As each lays from two hundred to six hun- 

 dred eggs, a few breeding females would fur- 

 nish a large stock of young. These young re- 

 spond readily to feeding and the resulting size 

 seems as much dependent upon the food as 

 upon the age of the individual. Large indi- 

 viduals and large races might be expected 

 from proper culture. 



Though the eggs are best cared for by the 

 mother, it was found possible to hatch them 

 in McDonald fish-hatching jars and thus rear 

 them under artificial conditions from a very 

 early stage. 



As each male is capable of fertilizing several 

 females and, moreover, as it was found that 

 in Cambarus the sperm may be kept all winter 

 in the receptacle of the female and used by 

 her to fertilize the eggs in the spring, few 

 males are needed for breeding and these could 

 be used as food in the winter before the 

 spring, when so many of them die. 



This kind of crayfish grew in the laboratory 

 to a lepgth of four inches in three and a 

 quarter years and was of marketable size, 

 three inches, at the end of the second summer 

 from the egg. Probably in the open it at- 

 tains its maximum size in four or five years. 



A second method of improving the supply 

 of crayfish, the introduction of other sjjecies, 

 seems a promising field for experiment, for it 

 has been found here that the eggs of the large 

 Oregon crajrfish, Asiacus, may be hatched in 

 the laboratory and reared as readily as in the 

 ease of C. afjinis, the native species. These 

 young Oregon crayfish grew here under such 

 artificial conditions to a length of 60 mm. in 

 five months from eggs hatched in the spring. 

 This large species has been sold for twice the 

 price of the eastern or the southern crayfishes, 

 and besides its larger size and weight it has 

 the advantage of more attractive and lobster- 

 like appearance, so that its introduction into 

 the east should be most acceptable. In fact, 

 large specimens brought here and kept alive 

 in the laboratory were as long as the six-inch 

 ' short-lobster ' now used as food, and if these 



crayfish were available in quantity they might 

 be used as a substitute for such young lobsters 

 and thus protect the lobster industry. 



As the scientific study of the geographical 

 distribution of crayfish leads to the conclu- 

 sion that the Oregon crayfish, Astacus, is ab- 

 sent from the whole eastern and central states 

 because its ancestors never got there and not 

 because of any natural obstacle to its living 

 there when once introduced, it would seem 

 well worth the while for the Bureau of Fish- 

 eries, and for private individuals, to introduce 

 large numbers of young and adult Astacus 

 into waters near markets not now supplied 

 with this superior article of food. Should it 

 be found that this large Astacus may be ac- 

 climated in the east to compete with Cam- 

 tar us, say in the Potomac, or better to take 

 the vacant places not now occupied by any 

 crayfish at all (such as the Connecticut River) 

 the catching of such introduced forms would 

 be a lucrative business that would add an ac- 

 ceptable article to the food drawn from fresh 

 waters. Even the artificial rearing of these 

 larger crayfish in central and eastern waters 

 awaits but the developments of time to be a 

 profitable side of fresh-water farming. 



A third means of increasing the available 

 food supply — the origination of larger races 

 of crayfish — may remain for a later stage of 

 the industry, but as we have more than sixty 

 species of Cambarus besides several species of 

 Astacus in this country and nine or more other 

 genera in other countries, the chances would 

 seem good for some future production of new 

 forms from crossing and selection. 



In Prance as far back as 1865 a successful 

 crayfish farm supplied Leon Soubeiran with 

 the data for making out the life history of 

 Astacus, and as we have found the habits of 

 Cambarus here so similar there seems no ob- 

 stacle to the establishment of crayfish farms in 

 the United States except the lack of a suffi- 

 cient demand' for crayfish as food. 



The needs of both Astacus and Cambarus 

 have been showh. in this laboratory to be 

 simply air, a small amount of fresh water and 

 organic food which may be a variety of refuse 

 animal and vegetable matter. The artificial 



