158 THE HISTOET OP ANIMALS. [B. VI, 



gobii, which bury themselves in the earth. The membrades 

 are produced from the phalerica. The trichides come from 

 these, and the trichise from the trichides ; from one kind of 

 aphya, which inhabits the port of Athens, the encrasicoli 

 are derived. There is another kind of aphya which originates 

 in the moenis and cestreus, but the barren aphrus is very 

 soft, and endures only for a short time, as I said before, and 

 at last nothing is left but the head and eyes. The fisher- 

 men, however, have now found a mode of conveying it from 

 place to place, for it lasts longer when salted. 



CHAPTER XV. 



1. EELS are not produced from sexual intercourse, nor are 

 they oviparous, nor have they ever been detected with semen 

 or ova, nor when dissected do they appear to possess either 

 seminal or uterine viscera ; and this is the only kind of san- 

 guineous animal which does not originate either in sexual 

 intercourse or in ova. It is, however, manifest that this is 

 the case, for, after rain, they have been reproduced in some 

 marshy ponds, from which all the water was drawn and the 

 mud cleaned out ; but they are never produced in dry places 

 nor in ponds that are always full, for they live upon and are 

 nourished by rain water. It is plain, therefore, that they 

 are not produced either from sexual intercourse or from ova. 

 Some persons have thought that they were productive, be- 

 cause some eels have parasitical worms, and they thought 

 that these became eels. 



2. This, however, is not the case, but they originate in 

 what are called the entrails of the earth, which are found 

 spontaneously in mud and moist earth. They have been 

 observed making their escape from them, and others have 

 been found in them when cut up and dissected. These 

 originate both in the sea and in rivers wherein putrid mat- 

 ter is abundant ; in those places in the sea which are full of 

 fuci, and near the banks of rivers and ponds, for in these 

 places the heat causes much putridity. This is the mode of 

 generation in eels. 



CHAPTER XVI. 



1. THE reproductive function is not active in all fish at the 

 same time or the same manner, nor are they pregnant during 

 the same length of time. Before the season of sexual inter- 



