208 ZOOLOGY. 
strong man to carry. The electric or galvanic apparatus consists of four 
longitudinal bundles, disposed in two pairs, one larger above, and a smaller 
below, against the base of the anal fin. The fasciculi are divided by longi- 
tudinal partitions into hexagonal prisms, and transverse divisions separate 
these into small cells. The cells are filled with a gelatinous matter, and 
the whole apparatus is abundantly supplied with nerves from the spinal 
marrow. In the Torpedo, these nerves come directly from the brain. 
The amount of electricity furnished by the Gymnotus is enormous. 
Faraday made a calculation in regard to a specimen of ordinary size 
examined by him, that a single medium discharge was equal to that from a 
battery of 3500 square inches charged to its maximum. It need not then 
be a matter of surprise that the Gymnotus is capable of killing a horse by 
repeated discharges ; which it does by applying its whole length along the 
belly of the animal when in the water. The method of capturing the 
Gymnotus made use of by the South American Indians, consists in driving 
a number of horses and other cattle into the muddy pools in which the 
electric eels abound. Roused from their retreats in the mud, the Gymnoti 
emerge into the water, and gliding in among the animals, give to them 
violent shocks. A succession of discharges results in weakening the eels 
to such a degree, as to make it a matter of little danger or difficulty to 
capture them. The Voltaic pile, formed by the electric apparatus of the 
Gymnotus, is much like that of the Torpedo; the column being longitudinal, 
however, in the natural position of the animal, instead of vertical. ‘The 
anterior or cephalic extremity is positive; the caudal negative; and the 
animal is capable of discharging any portion of its column. The substance 
occupying the cells is a dense albuminous liquid, with a small amount of 
common salt. Each cell is separate and independent, answering to the 
cell of the galvanic battery. This electrical power is not confined to the 
Gymnotus. Various species of Torpedo, one of which is found on the 
coast of Massachusetts, exhibit the same property in a high degree. Other 
electrical fishes are Malapterurus electricus, Trichiurus electricus, and Tetra- 
odon electricus. Some insects, too, as Redivivus serratus and Mantis 
electricus, are reported to give electric shocks. It may be proper to men- 
tion, in conclusion, that the electricity of the Torpedo and Gymnotus is 
capable of exhibiting all the effects of ordinary electricity, and is in most 
cases entirely at the command of the animal, whether to emit or withhold it. 
Crurpew#£. The fishes of this family exhibit considerable analogies to 
the Salmonoids, differing, however, in the absence of an adipose dorsal. 
Both maxillaries and intermaxillaries are employed in forming the margin 
of the upper jaw, instead of the usual introduction of the latter alone. The 
body is well scaled, the scales sometimes very large. Bones of the mouth 
variously provided with teeth, these occurring sometimes on the pectinated 
tongue. 
The fishes of this family are among the most useful and indispensable to 
man. It includes the anchovy, the sardine, the sprat, the various herrings, 
and the shad. The Anchovy, Engraulis encrasicholus (pl. 81, fig. 3), is a 
small fish, a few inches in length, distributed throughout Europe, and 
412 
