THE EEL FAMILY 



The fishes belonging to this family resemble one another in 

 the following particulars. The body is elongated and usually 

 round, though sometimes flattened from side to side ; it is always 

 flattened at the tail end. The vent is some distance behind the 

 head, and behind the vent is a long tail region becoming grad- 

 ually thinner. The dorsal and ventral fins are very long and 

 flexible, extending either to the extreme tip of the tail or right 

 round it, so that there is no distinction between them and the 

 tail fin. The pelvic or hinder side-fins are entirely wanting, the 

 breast-fins usually well developed. The skin is soft and extends 

 all over the head and gill covers ; there are no scales or only 

 rudimentary ones entirely imbedded in the skin. The body is 

 strong and muscular, and extremely flexible. The common eels 

 live in fresh water, but do not breed there ; there are several 

 marine forms found near the coasts like the conger, and a num- 

 ber of species inhabiting only the abysses of the ocean. The 

 members of the family are spread through all the tropical and 

 temperate zones, but absent in arctic and antarctic regions. 



The mode of propagation of these fishes has always 

 been a mystery, but recently some light has been thrown upon 

 it although it is by no means fully explained. The roes whether 

 hard or soft are difficult to recognise in most specimens, because 

 they are small and undeveloped ; but nevertheless they are always 

 present, extending nearly the whole length of the bell}^ cavity on 

 either side of the intestine. The young eggs in the females can be 

 recognised under the microscope even in the narrowest roes. The 

 female organ is band-shaped and not tubular as in most fishes ; 

 the eggs are borne along the outer side ; there are no tubes to 

 conduct the eggs to the exterior, but they escape b}- a small open- 

 ing behind the vent. The eggs when ripe must therefore become 

 free in the belly cavity before the)- are shed. The male organ, 



