Recreations in Natural History. 



355 



and crayfish before the oysters; but in the classification of 

 domestic economy, the latter are the most important. We 

 may, however, mention that both the lobster and the _ cray- 

 fish may be bred artificially and rendered a cheap article of 

 food. The lobster produces from 15,000 to 20,000 eggs, and 

 the crayfish upwards of 100,000. There is thus plenty of 

 material to work upon, and the principal apparatuses a breed- 

 ing trough, as shown in Fig. 10, to which we are indebted to 

 Dr. Phipson's work. 



Fig. 10. — Breeding troughs foe hatching eggs of Crustacea, etc. (Prom 

 a sketch taken at the College de France, Paris.) 



A. Cistern, a. a. a. Glass troughs, containing gravel : the water flows constantly 

 from one to the other in a gentle stream. B. Large trough for salmou, etc. 



We are so convinced that to be generally useful, scientific 

 books must be interesting, that we have given particular pro- 

 minence to that element in Dr. Phipson's labours, and we tire 

 glad to be able to recommend it strongly on that account. We 

 do not, however, wish to convey the impression that, because 

 it is popular, it is not scientific. This is certainly not the 

 case ; but the work belongs to the department of Recreational 

 Science, because it relates exclusively to matters that, although 

 not generally known, arc interesting and easily understood. 



vol. v. — ko. v. 



C B 



