BULLETIN OF THE UKITED STATES FISH COMMISSION. 387 



at least not to the extent that I had supposed. I had daily occasion to 

 observe how the young fry flourished, although undoubtedly many 

 young fish were devoured by the birds. The following was the result 

 of my observations: Last autuuiu, about the beginniug of October, I 

 had about 50,000 very fine young carp, 100 of them weighing about 2^ 

 X)0unds ; of Ci/prinus or/us I had only about 1,000. The weight of the old 

 carp, originally weighing 1 to 1^ pounds, had increased 100 to 150 per 

 cent. ; while the weight of the Cyprinus orfus had not increased quite as 

 much ; and all this in the face of the fact that 300 ducks, 100 geese, and 2 

 swans, not to mention a flock of wild ducks (which are particularly fond 

 of young fish), had staid on this pond all summer. Frog-spawn, which 

 carp-cultivators, as a general rule, carefully remove from their ponds 

 at the most suitable time, i. e., in spring, I shall certainly put in this 

 pond, where also during the coming year carp, Cyprinus orfus, ducks, 

 and geese are going to live together in peaceful harmony. Frog-spawn 

 forms a good, nourishing food for ducks, and consequently it will in- 

 crease the quantity of carp-food. I considered the above observations, 

 which are principally based on the change of matter (stoflf-wechsel), of 

 such importance as to deem it my duty to communicate them to my 

 fellow-workers in the cause of pisciculture. 



ON THE RACES OU VARIETIES OF CARP, BENVI.Vfi THE EXIST- 

 ENCE OF BL.IJE CARP ANO CiOl^O CARP. 



BvF. ZE«fTZ. 



[Translation. ] 



Lo"u^R Franconian District Fishery Association, WtiRZBURG. 



WuRZEURG, February 13, 1882. 



Honored Sir: To-day, at last, I find time to answer your inquiry 

 relative to blue carp and gold carp, and to return the enclosure of your 

 letter. 



Eesujme: There is no such fish as the blue carp, whether viewed 

 from the standpoint of the naturalist or from that of the pisciculturist, 

 and we will do all in our power not to increase, without any special ob- 

 ject, the nomenclature of the carp, which has, as it is, too many ndmes 

 and subdivisions. 



As it was my object not to report anything that is not authentic, I 

 have reached the above result by conferring with several of the most 

 experienced carj)-traders and carp-raisers, and I have likewise exam- 

 ined a large number of different carp, some of them in tanks, all of 

 which will sufficiently excuse my delay in answering your letter. 



There are three principal races or varieties — not special kinds — of 

 carp : 



(1) The SCALE-CARP, Cyprinus carpio (Fv&[ich; Carpe commune), the, 



