[17] THE EEL QUESTION. 479 



among eels which had been caught during their migration to the sea, 

 and like the female eels which were migrating showed an entirely empty 

 stomach, containing only a small quantity of slime. A farther advanced 

 development of the lobe-organs, in contradistinction to those caught 

 during summer near Trieste, could not be noticed in any of them. 



Before entering upon the third and concluding portion of this treatise 

 on the eel question, I must describe and determine scientifically the 

 varieties of eels found in the lagoon of Comacchio. As I could not discover 

 au actual difference of species, they must all come under the common 

 designation of Anguilla fluviatilis (Fleming). I give the distinguishing 

 marks of the different varieties according to Siebold.* 



Distinguishing marks of the species. — Lower jaw longer than the upper 

 jaw ; dorsal fin begins far behind the head, anal fin begins the length 

 of a head back of the beginning of the dorsal fin ; body, as far as the 

 anus, cylindrical ; from there to the tail, compressed. 



Of this species the following sexual varieties can be distinguished : 



(1.) Anguilla fluviatilis, Femina vera. — The fully developed female 

 eel : Snout generally broad, dorsal fin comparatively high, color on the 

 whole light, back brownish green — never intensely black ; belly whitish 

 yellow; little or no metallic glitter ; flesh coarse and firm; grows more 

 than one meter in length ; the frill-like ovarium contains much fat, and 

 the eggs contain many yolk-grains. Migrates to the sea in autumn, and 

 during that time ceases to eat. 



(2.) Anguilla fluviatilis, Femina sterilis. — The barren female eel, called 

 in Comacchio "pasciuto": Snout decidedly broad, dorsal fin high, eyes 

 remarkably small, color green — almost yellowish, back green, belly yel- 

 low, no metallic glitter, flesh soft and tender, grows three-quarters of a 

 meter in length ; the ovarium contains no fat, and is, near the edges, 

 frothy, thin, and bright, often as transparent as glass; the eggs contain 

 few or no yolk-grains. Never migrates to the sea and fee ds all the year 

 round. 



(3.) Aguilla fluviatilis, Mas.fi) — The eel with a lobe-organ (the male 

 eel?): Snout either attenuate and pointed, or short and pointed; dorsal 

 fin narrow, eyes generally large, color decidedly dark, the back a dark 

 green, often quite black ; belly bluish or silvery white with little or 

 no yellow, has a metallic glitter, often a bronze color; flesh coarse 

 and firm ; so far no specimens have been found measuring more than 

 48 centimeters. Instead of the frill-like ovarium, it has an organ 

 resembling a narrow band divided into many lobes, probably of the 

 nature of testicles. Migrates to the sea in autumn, and during that time 

 does not take any food. 



According to size and weight the Comacchio fishermen distinguish 

 the eels by different names. The young eels, thin as threads, which in 

 spring come from the sea they call u Capillari^ those weighing less than 



* With his usual iugeuuity Siehold as far back as 1863 (Siisswasserhsche Mitteleuro- 

 pas, p. 352), asked the question, whether those eels which never migrate could be bar- 

 ren eels, whilst the migrating eels were the fully developed males and females. 



