176 MEMOIRS OF THE CARNEGIE MUSEUM. 
found to be correct. His second group contains all of the long-mouthed forms, 
Sternarchorhynchus, Sternarchorhamphus and Rhamphichthys. These he thinks 
must feed on insects. In this he was mistaken. The stomachs of these species 
which were examined contained mud-inhabiting forms. His third group includes 
the remaining Gymnotide. He regards the toothless forms of this group to be 
plankton-feeders, and cites Sternarchogiton and Steatogenys as examples. The 
first mentioned was not examined. Three stomachs of the latter contained the 
larvee of insects and Annelida as well as entomostraca, with Annelida much pre- 
ponderating. The forms with teeth he gives as feeding upon small water-insects 
and perhaps vegetable matter. Sternopygus was found to feed upon water-beetles 
in particular, but also upon fish and freshwater shrimps. Higenmannia on the 
contrary took very few insects, but a great number of entomostraca and larvee 
of insects. 
Summary. 
1. Entomostraca supplemented by the larvie of insects form the main food 
of the young of all species examined. 
2. Only the adult large-mouthed species fed upon freshwater shrimps and 
fishes. 
3. The adult small-mouthed species feed upon entomostraca, insect larve, 
and adult insects. 
4. The long tubular-mouthed species are bottom-feeders. Their food is 
mud-inhabiting forms, Annelida, and insect larvee, sucked up with the surrounding 
mud. 
Reproduction. 
Nothing is known of the breeding habits of the Gymnotide. Several unsuc- 
cessful attempts have been made to obtain embryos or very small electric eels. 
This failure has tended to confirm the belief of the natives that the electric eel 
as well as the other Gymnotide brings forth living young. But no Gymnotids 
have ever been captured containing embryos, nor is the construction of the genital 
tracts such as would favor this view, except in one particular. In most species 
there is a more or less well developed papilla at the terminal opening of the sex 
ducts just below the head. Sachs (116 et seq., |. c.) was of the opinion that the 
electric eel lays eggs. He collected several females with ripe eggs in February and 
March. He thought the period of laying to be in the early part of the rainy season, 
that is, the last of December and the first of January. Miller (Bull. Am. Mus. 
Nat. Hist., Vol. XXIII, 1907) states that he took many females of Gymnotus carapo 
with eggs from the swamps and a sluggish stream near Los Amates, Guatemala, 
on Feb. 20, 1905. The largest of them was 200 mm. long. Among the specimens 
of Higenmannia virescens and Sternopygus macrurus collected by Dr. C. H. Eigen- 
mann in Georgetown are many females with eggs. Several females of Higenmannia 
are very noticeably distended. Some of the specimens which I took from the 
same place on Sept. 26, 1910, contained eggs, but they did not seem as nearly ripe 
