Acanthopterygii; Synentognathi 211 
the eastern United States, often ascends the rivers. Tylosurus 
raphidoma, Tylosurus fodiator, Tylosurus acus, and other species 
are very robust, with short strong jaws. Athlennes hians is a 
very large fish with the body strongly compressed, almost 
ribbon-like. It is found in the West Indies and across the 
Isthmus as far as Hawaii. Many other species, mostly belong- 
ing to Tylosurus, abound in the warm seas of all regions. 
Tylosurus ferox is the long tom of the Australian markets. 
Potamorrhaphis with the dorsal fin low is found in Brazilian 
rivers. A few fossil species are referred to Belone, Belone flava 
from the lower Eocene being the earliest. 
The Flying-fishes: Exocetide.—The family of Exocetide in- 
cludes the flying-fishes and several related forms more or less 
intermediate between these and the garfishes. In these fishes 
the teeth are small and nearly equal and the maxillary is sepa- 
tate from the premaxillary. The third upper pharyngeal is 
much enlarged and there are no zygapophyses to the vertebre. 
The skippers (Scombresox) have slender bodies, pointed jaws, 
and, like the mackerel, a number of detached finlets behind 
dorsal and anal, although in other respects they show no affinity 
to the mackerel. The common skipper, or saury (Scombresox 
saurus), is found on both shores of the North Atlantic swimming 
in large schools at the surface of the water, frequently leaping 
for a little distance like the flying-fish. They are pursued by 
the mackerel-like fishes, as the tunny or bonito, and sometimes 
by porpoises. According to Mr. Couch, the skippers, when 
pursued, ‘“‘mount to the surface in multitudes and crowd on 
each other as they press forward. When still more closely 
pursued, they spring to the height of several feet, leap over 
each other in singular confusion, and again sink beneath. Still 
‘further urged, they mount again and rush along the surface, 
by repeated starts, for more than one hundred feet, without 
once dipping beneath or scarcely seeming to touch the water. 
At last the pursuer springs after them, usually across their course, 
and again they all disappear together. Amidst such multi- 
tudes—for more than twenty thousand have been judged to 
be out of the water together—some must fall a prey to the enemy; 
but so many hunting in company, it must be long before the 
pursuers abandon. From inspection we could scarcely judge 
