SIEBOLD's EUROPEAN FRESKWATEE- FISHES, 27 



- -r . 111^ TT 1 J ( Alburniis lucidiis 



4. Leuciscus dolabratus, Holandre | y^^ialius cephalus 



_ ^, , ^ 1 A • ( Chondrostoma nasus 



5. Chondrostoma rysela, Agassiz ^^ ^^^^^^^^ agassizii. 



The least doubtful is the first, but then we must not forget that 

 this Carpio kollarii is the produce of two domesticated species, viz. 

 the Carp and Crucian Carp, and therefore that this instance per se 

 onJj proves that hybridism is possible in this class of vertebrate 

 animals. The other instances certainly need confirmation : and 

 nobody who looks over the list given above, will fail to remark that 

 in every case, the fishes said to be the parents of these hybrids, are 

 referred to two different genera, and are thus not the offspring of 

 closely allied species of the same genus, as we should expect a priori.'^ 



Surely there is something wrong here ! Either the genera are based 

 upon merely specific characters, and not entitled to that rank in our 

 system, or the explanation of the origin of those hybrids, and even 

 their hybrid nature itself becomes a matter of great difficulty. Dr. 

 V. Siebold himself is evidently wavering : for whilst he asserts his 

 conviction that the fishes are hybrids, he not only prefixes to their 

 descriptions the heading " characters of the species," but actually 

 forms two new genera, viz. Ahramidopsis for A. leuchartii, and Blic- 

 copsis for A. ahramo-rutilus ! Not even Heckel or Bonaparte would 

 have been guilty of such an inconsistency as this, and we can only 

 partly account for it from the author's former studies of the lower 

 classes of the animal kingdom, where many genera are founded upon 

 larval forms. 



The question whether these hybrids are fertile, is not solved ; 

 but their sexual organs were found to be fully developed. 



The discovery of the author, that there are individuals of certain 

 species, especially of the Salmonoids, but perhaps of all other fami- 

 lies, which remain sterile throughout their life, assuming with age a 

 form very different from that of individuals with the sexual organs 

 normally developed, is scientifically of the greatest importance, and 

 will engage Ichthyologists for some time to come. A speedy con- 

 firmation of it is the more wanted, as should these barren fish 

 occur in considerable numbers, the question would assume a practical 



* Ornitliologists who call to mind the hybrids between different species of ducks, 

 will, perhaps, not find any thing sui'prising in this, but a genus in Ichthyology is 

 generally more comprehensive than one in Ornithology. 



