PISCES. 217 
New York, and in those of the Mississippi valley. They will probably be 
discovered in the eastern rivers (in the Hudson at least), when their ichthy- 
ology has been more fully studied. Marine forms are met with in 
Galeichthys, Arius, and Bagrus, the former characterized by the high dorsa! 
and pectorals. 
South America exhibits some Si/uroids of especial interest. Conspicuous 
among these are Arges cyclopum, or Pimelodus cyclopum of Humboldt, 
and Brontes prenadilla, which inhabit the highest regions in which fish are 
known to live. They are found in Quito, at elevations of more than 16,000 
feet above the level of the sea, living in the streams running down the sides 
of Cotopaxi and Tungaragua. The most interesting fact in the history of 
these fishes is, that they are frequently ejected from the craters of the above- 
mentioned volcanoes, in immense numbers; the supply being probably 
derived from the subterranean lakes in the body of the mountains. Our 
space will not permit us to mention any other members of this interesting 
family, excepting the Malapterus electricus, the Silurus electricus of older 
authors. This species is characterized generically by the absence of the 
first dorsal, the adipose dorsal alone existing, as also by the possession of an 
electric apparatus or battery, somewhat intermediate in character between 
those of Gymnotus and Torpedo, although of much finer texture. The 
whole body beneath the integuments is inclosed by the apparatus in two 
layers of great compactness, and at first sight suggesting a deposit of fat. 
A dense fascia separates the battery from the muscular system. The cells, 
formed by transverse and. longitudinal fibrous partitions, are rhombic in 
shape, and exceedingly minute. The nerves of the outer organ come from 
branches of the fifth pair of nerves, the inner organ is supplied by the inter- 
costal nerves. The direction of the current is probably from the head to 
the tail; the cephalic extremity being positive, and the caudal negative. 
We now come to the third order, Pharyngognathi, of our classification, 
divided into two sub-orders, Malacopterygit, or soft finned forms, and 
Acanthopterygit, or spiny finned. The only family belonging to the first 
division is that of the : 
Scomperesocip#, characterized by a structure intermediate between 
that of Hsocide and Scombride. 'The body is greatly elongated, and the 
jaws produced into long, very narrow beaks. The scales are minute, and 
hardly apparent in some species, The more conspicuous genera are Belone 
and Scomberesox ; the former having a considerable external resemblance to 
the gar-fish, Lepidosteus, but with very minute soft scales, the latter having 
the posterior portion of the anal and dorsal divided into finlets, as in the 
mackerel, in other respects like Belone. This last mentioned fish is repre- 
sented by several species in North America, one of which, B. truncata, 
occasionally penetrates the Atlantic rivers, as the Delaware and Susque- 
hanna, and is known also as the silver-gar, or bill-fish. Neither genus is 
of any economical value. Inconspicuous in this respect, also, are the 
families Caromip®, Cycio-Lasrin#, and Creno-Lasrin”, sufficiently cha- 
racterized by the spurious fin rays, and the ordinal characteristics. The 
old family of Labride, including the two latter sub-divisions, which differ 
421 
