he family
_Siluridae_, which has since been broken up by T. Gill and other
American authors into several families, united under the name of
Nematognathi. A middle course appears the more reasonable to the
present writer, who has divided the _Siluridae_ of Cuvier into three
families, with the following definitions:--

_Siluridae_--ribs attached to strong parapophyses; operculum well
developed.

_Loricariidae_--ribs sessile; parapophyses absent; operculum more or
less developed.

_Aspredinidae_--ribs sessile; strong parapophyses; operculum absent.

These three families may be defined among the Ostariophysi by having the
parietal bones fused with the supraoccipital, no symplectic, the body
naked or with bony scutes, the mouth usually toothed, with barbels, and
usually an adipose dorsal fin.

The _Siluridae_ embrace more than one thousand species, spread over the
fresh waters of all parts of the world, but mostly from between the
tropics. They are absent from western Europe and north-west Africa, and
from North America west of the Rocky Mountains, but this deficiency has
been made good by now, the introduction of _Amiurus nebulosus_ and
allied species in various parts of continental Europe and California
having proved a success. Only a few forms are marine (_Plotosus_,
_Arius_, _Galeichthys_).

[Illustration: FIG. 1.--The "Wels" (_Silurus glanis_).]

The species which has given the name to the whole family is the "Wels"
of the Germans, _Silurus glanis_, the largest European fresh-water fish,
inhabiting the greater part of Europe from the Rhine eastwards and north
of the Alps. Its head is large and broad, its mouth wide, furnished with
six barbels, of which those of the upper jaw are very long. Both jaws
and the palate are armed with broad bands of small closely-set teeth,
which give the bones a rasp-like appearance. The eyes are exceedingly
small. The short body terminates in a long, compressed, muscular tail,
and the whole fish is covered with a smooth, scaleless, slippery skin.
Specimens of 4 and 5 ft. in length, and of 50 to 80 lb. in weight, are
of common occurrence, and the fish grows to 10 ft., with a weight of 400
lb., in the Danube. Its food consists chiefly of other bottom-feeding
fishes, and in inland countries it is considered one of the better class
of food fishes. Stories about children having been found in the stomach
of very large individuals are probably inventions. An allied species
(_S. aristoteli