Miscellaneous. 443 



The eels in which M. Syrski discovered what he regards as the 

 male organs, differ from the others by several characters, and especi- 

 ally by their small size and the great volume of their eyes. 



Having been engaged during last year in a revision of the Anguil- 

 liforra fishes, I have been able to ascertain the correctness of the 

 facts announced by M. Syrski ; and I have convinced myself that in 

 many individuals of the species Anguilla vulgaris there exist, # in place 

 of the ovaries, organs of very different form and structure, which are 

 very probably the male organs. I have also ascertained that these 

 individuals differed from the others by their small size and their 

 large eyes. They all belong to the variety known in France as the 

 Anguille pimperneau, which does not ascend rivers, but remains 

 always at their mouths, and at the expense of which Kaup has 

 formed three distinct species under the names of Anguilla Cuvieri, 

 A. Bibroni, and A. Savignyi. As I have hitherto been unable to 

 investigate these animals elsewhere than in the collection of the 

 museum and in individuals preserved in alcohol, I could not, any 

 more than M. Syrski, detect the presence of spermatozoids ; but for 

 many reasons, which I cannot here develop, I share his opinion as to 

 the testicular nature of the organs discovered by him. 



There is, however, one point upon which I cannot agree with M. 

 Syrski ; and it is that these small eels, of the variety called pimper- 

 neau, do not exclusively belong to the male sex. I have ascertained 

 the existence of perfectly well-characterized ovaries in several in- 

 dividuals belonging to this variety. 



From this observation it follows that the Anguille pimperneau, an 

 essentially marine variety which does not ascend rivers, possesses 

 both sexes ; while those which ascend rivers and which belong to the 

 varieties called Latirostres and Acutirostres present only female indi- 

 viduals, in which, however, the ova never arrive at maturity, and con- 

 sequently they always remain barren. 



The eels of North America do not differ specifically from those of 

 Europe; and we find there the same varieties of form. That which 

 represents our pimperneau, and which Kaup has described under the 

 name of Anguilla novai aurelianensis, has furnished me with the 

 form of reproductive organs which I regard as belonging to the 

 male sex. 



The species Anguilla vulgaris would therefore present a sexual 

 form (the pimperneau) and several sterile forms. This very remark- 

 able fact, however, is not isolated in fishes, since we meet with 

 analogous facts in the carp. 



I have found these male organs in some individuals of another 

 species of eel, Anguilla marmorata, which belongs to the Indian 

 Ocean. Here the deficiency of materials has prevented my ascer- 

 taining the existence of a completely sexual form and of sterile 

 forms. — Comptes Rendus, July 19, 1875, p. 159. 



