ROOM XT.] NATURAL HISTORY. 53 
Gar-Fish ( Esox belone), the jaws are slender, and very 
much elongated. In one genus, the Half-Beak ( Hemi - 
ramphus), the lower jaw alone is elongated and the mouth 
oblique, and placed at its base. The Flying-Fish 
( Exoceti ) belong to this family; they inhabit the seas of 
warm and temperate climates, and are peculiar for the 
great length of the pectoral fins, which enables them to sus- 
; pend themselves in the air as long as the tins continue moist. 
On leaving the water, to escape from the pursuit of their 
enemies in that element, they often become the prey of 
! birds, which are continually on the watch to attack them. 
The Mormyri (Mormyri) are fresh water lish of Africa, 
which have a small mouth, and the gill-fiap hid under 
the skin. 
The Siluroid Fish ( Siluridce ) have a naked skin, in 
which large bony plates are frequently imbedded. They 
have often a soft dorsal fin, and their intermaxillaries edge 
the jaws, their maxillaries forming only beards. 
Many of these have the first ray of the pectoral fin very 
strong and bony, and the animal has the power of fixing 
it immoveablv, so that it forms a dangerous weapon, and 
the wound inflicted by it is said to be venomous; but this, 
perhaps, greatly depends on the liability of persons in 
warm climates to tetanus or locked jaw from penetrating 
wounds. They live chiefly on vegetable food, especially 
seeds. Their flesh is very fat, and much used as food ; 
but that of some species, as the Shals ( Synodontes ) of 
Senegal, is reputed to be dangerous. The skin of some of 
the genera, as the Callichtes ( Callichtes ), is covered with 
four rows of large imbricate scales, which protect the body, 
like scale-armour ; and others, as the Loricaria ( Loricarice ), 
have the body entirely covered with a hard coat, formed 
of angular scales. 
The Salmons ( Salmonidce ) have, like most of the Siluri, 
a soft, false, rayless, hinder dorsal fin, but the body is 
covered with regular scales. They principally ascend 
rivers to spawn. They are voracious, and prey on insects 
and small animals. This family has been divided into 
several genera, according to the form and presence of the 
teeth, and the position of the fins. 
Cases 5 and 6. The Herrings ( Clupeidce ) have a 
