5-TWO FERTILE CYPRINOID HYBRIDS. 
By KARL KNAUTHE. 
[Translated from the German: Zoologischer Anzeiger, vol. 16, pp. 416-418, October 30, 1893.] 
[A hybrid between the common carp {Cyprinus carpio) and a species closely related to the 
goldfish known as the Karausche {Carassius carassius or vulgaris) is not uncommon in some parts of 
Germany, and is intermediate between the two in form, squamation, fins, and the pharyngeal teeth. 
Although generally recognized as a hybrid and known by a name indicating its parentage, a com- 
pound of the names of the two parents, Karpf-Karausche {Earpf, the true carp, and Karausche, the 
crucian carp), a distinctive generic and specific name {Carpio kollari) is given to it by German ich- 
thyologists. No experiments ap^iear to have been made to ascertain the fertility or character of the 
jirogeny of these hybrids until lately. The following article, therefore, supplies a want and will be 
of interest to carp-culturists. There are no records of the occurrence of the so-called Carpio TcoUari 
in the United States (or indeed of any other cyprinoid hybrids), and attention should be directed to 
those places where the carp and goldfish commingle. — Theodore Gill.] 
If I am not mistaken there are at present no positive observations that Carpio 
kollari Heck, or any other of the known hybrids between any of our cyprinoids, are 
fertile. Von Siebold, it is true, long ago found fully developed ovaries in hybrid carps 
(“Fresh-water Fishes of Middle Europe,” Leipzig, 1863), and recently District Magis- 
trate Lambateur reported to Prof. Landois “that the fish spawned in the months of 
March and April ” (“ Westfalens Thierleben,” Fische, Munster, 1892), yet this eminent 
zoologist seems to partly doubt the correctness of this observation. 
This year, in order to clear the matter up, I have made different experiments with 
full-grown typical examples of Carpio kollari, as well as with Alburnus leydigii {Alhur- 
nus lueidus x Leucaspnis delineatus) in numerous clay pits of my own make. The 
pools, perfectly constructed ponds, were protected against ducks, geese, etc., by high 
barbed-wire fences, had lain dry a long time, and were exclusively stocked with the 
specimens for experimenting; to these they offered, with a rich food supply, excellent 
spawning-idaces. 
In the first pit there were put 2 females of Carpio kollari Heck and 1 male of Cypri- 
nus carassius L. 
In the second pit there were put 1 male of Carpio kollari Heck and 2 females of 
Cyprinus carassius L. 
In the third j)it there were put 3 males of Carpio kollari Heck and 6 females of 
Carpio kollari Heck. 
The spawn was surprisingly sparse aud, besides, about GO per cent of the fry died 
during the first days of life. (The same occurred this year with the fry of pure carps 
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