620 NATURAL HISTORY OF AQUATIC ANIMALS. 



tect it more efficiently from the accidents incidental to transfer, as also against inimical or hurtful 

 attacks in the ponds (the Mirror Carp having very few and the Leather Carp no scales), is not 

 correct. In transportation scales are not only inefficient for protection, but they frequently cause 

 the death of the fish, especially in transporting the so-called breeding fish ; for if a scale be torn off 

 in part only ulceratiou will ensue, and the fish, of course, will die. Again, should any scale be lost, 

 the bare spot will very soon begin to fester, or develop a confervaceous growth, and the conse- 

 quences will be the same. On the contrary, the Leather Carp, which oddly enough, like the frog, 

 is destitute of covering, will bear a great deal more ill-usage and injury, whether young or old, 

 than the Scale Carp. The smooth, slippery skin of the Leather Carp suffers much less from fric- 

 tion during transportation than the Scale Carp, and any slight wound will heal up much more 

 easily, as the epithelium will cover it immediately and the formation of a new skiu can progress 

 under its protection. I have often had the opportunity of seeing such scars upon the skin of the 

 Mirror Carp, and even more so on that of the Leather Carp. They are the effects of injury 

 from the sharp edges of the heron's bill, the bite of a pike, or some other hurt, and I never saw 

 anything of the kind on a Scale Carp, for if one of these be wounded it almost invariably dies. 



The Carp will sometimes cross with some related species of the Cyprinidtf, for instance, Caras- 

 sius vulgaris; and, in consequence, hybrids have been engendered which sometimes resemble the 

 genuine Carp so much that it is often difficult for the student as well as for the professed culturist 

 and experienced fisherman to immediately recognize them. Such fishes are valueless as food, on 

 account of their bad and very bony flesh. One of the hybrids mentioned is the Carpio Kollarii 

 Cyprinus striatus, which was formerly regarded as a separate species. It is a cross between the 

 Carp and Carassius vulgaris (crucian Carp), a very poor and bony fish, which, in Germany, is some- 

 times called "Poor man's Carp." Some varieties exist of this common fish. The latter has even 

 been dignified by a specific name of its own, Carassius gibelio, 



The spawning seasons of the crucian and the true Carp coincide, and, where kept together, 

 hybrid races may readily be formed; that period including the time from the month of May until 

 August. 



In order to determine this question, I myself managed to bring about such crosses by placing 

 (1) female common Carp with male crucian Carp, and (2) female crucian Carp with male common 

 Carp, in small tanks, constructed with this end in view; (3) I also put together female Carpio Kol- 

 larii with male common Carp; this for the sole purpose of testing the capability of propagation of 

 the C. Kollarii, which had been doubted. In the two former cases I obtained forms analogous to 

 the Carpio Kollarii sometimes approaching in appearance the true Carp, at others the crucian 

 Carp. In the third case, however, having placed ripe Carpio Kollarii together with Cyprinus 

 carpio, I obtained a product with difficulty to be distinguished from the genuine Carp. I took 

 the trouble to feed tuem for three years, in order to try their fitness for the tSble, but their flesh 

 was exceedingly poor and very bony, and could not be compared by any means to that of the 

 common Carp. 



Considering, then, the whole extensive tract of country devoted tD fish-culture in Central 

 Europe, where crucian Carp are to be found from Italy to Sweden and Norway, from France to the 

 boundary of Eastern Siberia, considering the many who cultivate on a small scale and the owners 

 of badly stocked ponds, with their different doubtful productions, how often do we find in the 

 markets or ponds very nice crosses which have been propagated through from three to ten gen- 

 erations and which are sold for Carp! There are many small sheets of water in Germany, France, 

 Austria, Italy, Holland, and Belgium, and probably also in England, the proprietors of which 

 imagine, in good faith, that they have stocked their ponds with good, genuine Carp, which in 



