262 AMERICAN FISH CULTURE. 



be doubtful whether it can be propagated even there at 

 first, and the habits of the species must be still more closely 

 studied in order to ascertain why it should have proven 

 sterile in the West Indian islands and Cayenne. It cannot 

 have been on account of want of sufficient heat, for the 

 mean temperature is not very different from that of Mauri- 

 tius j nor can it be due to the difference in time of the sea- 

 sons, for the species has been successfully acclimatized in 

 China, which is north of the tropics, as well as in Mauri- 

 tius and Reunion. The cause of sterility is, therefore, at 

 present inexplicable ; but when it is known, it may perhaps 

 be counteracted. It would appear to be extremely doubt- 

 ful whether the species can be introduced and reared in 

 France ; but yet it must be remembered that so eminently 

 experienced and scientific a man as M. Coste, the acade- 

 mician, has pronounced the opinion that it can be effected, 

 and he has published instructions to guide those to whom 

 carriage of specimens may be intrusted. Possibly by per- 

 sistence of effort, and by selection of hardy individuals for 

 stock, success may eventually be attained ; and if such can 

 be had for France, there seems to be no reason why like 

 fortune should not be expected in the United States, as far 

 north as the latitude of Virginia. Doubtless, the fish 

 would be a very valuable acquisition if it could be reared, 

 and the more so as it is herbivorous, while the most es- 

 teemed fishes, found in the more temperate regions of the 

 United States, are more or less carnivorous. 



Rules for transportation and introduction. As to the 

 introduction, it would, probably, be more readily effected by 

 the transportation of nests with the ova, than by that of 

 the fishes themselves, and such a course would at least re- 

 quire less care and attention, and would have the additional 

 advantage of furnishing so many more individuals to select 



