EEL TRIBE. 
45i 
without trouble it may obtain access to air.” Indeed, the chief respiration of 
this fish is carried on by means of the two sacs on the sides of the neck, which 
can be inflated and emptied at will. In the other two fresh-water genera, one of 
which ( Monopterus ) is confined to the Oriental region, while the other (Synibran- 
•chvs) has a distribution coextensive with that of the family, there is no additional 
breathing-organ, the body is naked, and the pectoral girdle is attached to the 
skull. Whereas in the former of these genera the gills are rudimenta], in the 
latter they are well developed ; and, in the absence of an accessory apparatus, it 
seems strange how the one species with rudimental gills manages to breath at 
all. The Bengal short-tailed eel (Syvibranchus bengalensis) has been selected to 
illustrate the external form of the members of this very remarkable family. 
electric eel (J nat. size). 
Together with four other genera from the fresh waters of Tropical 
El6ctric y.pl ® ^ ^ 
America, the well-known electric eel (Gymnotus electricus ) constitutes 
the third and last family of the group under consideration, the leading charac¬ 
teristics of which are as follows. The jaws are formed in the same manner as in 
the true eels, and the head is scaleless and without barbels. The dorsal fin is 
either totally wanting, or reduced to a fatty rudiment; the anal is extremely 
elongated; pelvics are wanting : and the caudal is likewise generally absent, the 
tail terminating in a point, which, when broken off, can be renewed in the same 
manner as in the blind-worms. The vent is situated in or near the throat; the 
gill-openings are rather narrow; an air-bladder is present; the stomach has a 
blind appendage; and the ovaries are provided with ducts. In the skeleton the 
pectoral girdle is attached to the skull. By Professor Cope the typical genus is 
considered to be to a certain extent intermediate between the last family and the 
■eel-like representatives of the cat-fishes. 
