BULLETIN OF THE UNITED STATES FISH COMMISSION. 105 



layer to yield ; these eels had foimd their way between the boards as 

 frj', where they had found sufficient food and had grown to such a size 

 that the pressure of their united strength had pushed up the roof of 

 their j)rison. These facts, observed by an old millwright, were com- 

 municated to me by Privy Counsellor Schmid, of Maricnwerder, who 

 supervised the construction of the Miihlhof dam, and he fully confirmed 

 them. 



Eels of 4 inches in length, which in May are plenty in fish-jionds, by 

 the end of October reach a length of 10 inches and the thickness of a 

 man's little finger; in the following fall they measure from 20 to 24 

 inches, and in the third year are ready to be eaten. On account of their 

 rapid growth and hardy nature, in consequence of which latter they 

 live in mud-holes and unprofitable waters of all kinds, the breeding of 

 eels is a very remunerative business. The young fish (of which, at the 

 time of their first appearance at the mouths of rivers, it takes 1,500 to 

 1,700 to make a pound, while, when taken later and a little further from 

 the sea, it takes only 350 to 400 for the same weight) may be obtained 

 at low prices from France through Hiiniugen, or in Germany from 

 Eandesberg and, through the Berlin Aquarium, from Wittenberg, and, 

 when the temperature of the air is not too high, may be carried in soft 

 moss throughout all Germany. 



According to the statement of the well-known Paris fish-merchant, 

 Millet, two pounds of eels, planted in a muddy pond in 1840, in five 

 years yielded 5,000 pounds of fine eels. 



XVIII. Observations of Dr. Hermes in 1881 on the conger. 



The observations of Dr. Otto Hermes, director of the Berlin Aquarium, 

 who has recently discovered the true nature of the organ of Syrski in 

 the conger, are extremely interesting. 



'' Since Syrski, in 1874, found the organs in AncniiUa vulgaris — which are 

 called by his name, and which, by him and most zoologists, were taken 

 for the male reproductive organs — it is only necessary that a ripe male 

 eel should be found in order to settle forever the question of the sexes 

 of the eel. Up to this time all efforts have failed to reach the desired 

 result. The histiological investigations of the Syrskian organs pursued 

 by S. Freud render it more i)robable that these were young roes ; yet 

 there remained all the time a doubt, since the spermatozoa had not been 

 actually observed, and this uncertainty is an insuperable obstacle to the 

 acceptance of the Syrskian discovery. The supposed discovery of sper- 

 matozoa by A. S. Packard in the male eel proved to be another delu- 

 sion. The contradiction of this imaginary discovery appeared in No. 26 

 of the second volume of the Zoologische Anzeiger, p. 193, in which it 

 was stated that the motile bodies were not spermatozoa, but yolk par- 

 ticles. This correction was also made by Yon Siebold's assistant, Dr. 

 Paul,* and by S. Th. Cattle. 



^Austrian Fishery Gazette, 1880, No. 12, p. 90. 



