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GILL] LIFE HISTORIES OF TOADFISHES 391 
Beaufort, N. C., species of Prionotus are designated as flying toads. 
In England, toadfish is a little used synonym of the angler. In 
other countries, where the Batrachoidids are unknown, the -Tetra- 
odontids are almost universally designated as toadfishes, and the 
name in Australia and the Cape Colony always suggests those 
fishes and those only. Sapo is the Spanish equivalent of toad and 
in partly Spanish-speaking countries, as Florida and California, the 
name is used for the Batrachoidids. 
OpsANUS 
The genus Opsanus has a naked and rather loose thick skin and 
the head more or less beset with skinny tags; the opercle has two 
Fic. 106.—Southern toadfish (Opsanus pardus). After Goode. 
divergent spines, the suboperculum two nearly parallel spines, or 
rather branches of one spine, of which the lower is much shorter, 
and the spinous dorsal has three short stout spines. The upper sur- 
face of the cranium has a median longitudinal ridge, and also a 
transverse one, together forming a T-shaped figure which is quite 
prominent in a dried skin, and suggested to Linnzus the singular 
name (tau, Greek for T) which he gave to the common species. 
Like some others, but not all of the family, the toadfishes of 
the genus Opsanus have a pair of pocket-like sacks opening exter- 
nally, one on each side, by a pore in the axil of the pectoral fin. 
The function of these sacks is unknown. Sorensen (1884) com- 
pared them with similar sacks of catfishes (Silurids), concerning 
which he remarks that “it would not be unreasonable to suppose 
that we had to deal with a case of poisonous secretion. But such 
an explanation cannot be considered acceptable, both because the 
sack can by no means be said to open close to the spine, and also 
because the only fishes probably in which an at least analogous 
