324 FISHES 



surface. The whole nest is thus somewhat like the ark of bul- 

 rushes which served as a cradle to the infant Moses. In this nest 

 are deposited about a thousand amber-coloured eggs, a fifth of an 

 inch in diameter, which hatch in five days. After about eight- 

 teen days the fry leave the nest, they are then three inches long. 

 The construction of the nest was not observed, nor was a parent 

 fish found guarding it, but Budgett was informed by the natives 

 that the parent is usually present and defends the nest with 

 formidable bites. This nest was studied in the swamps of 

 McCarthy Island in the river Gambia and in the same swamps 

 were found the enormous nests of Heterotis, the African genus 

 of the Osteoglossidae. These nests are four feet in diameter 

 enclosed by walls eight inches thick made of the grasses re- 

 moved from the interior while the bottom is the smooth bare 

 ground of the swamp. They have the appearance of miniature 

 lagoons among the dense aquatic vegetation. The eggs of 

 the fish, which are about a tenth of an inch in diameter, cover 

 the bottom of the nest and hatch in two days. Sarcodaces odoe, 

 an African species of the Characinidae, lays in the same swamps 

 its eggs in a floating foam formed of some secretion enclosing 

 bubbles of air and when the larvae are hatched they hang for 

 some time from the surface of the water by means of a large 

 sucker-like organ on the front of the head. 



Many of the cat-fishes (Siluridae) make some sort of nest 

 and take care of their eggs. The common horned pout, 

 Amiurus nebulosus, of North America, and other species of the 

 genus, deposit their eggs in holes under logs or in old pails or 

 other receptacles thrown into the water, or in holes excavated 

 in the mud. Both parents co-operate in the preparation of the 

 nest, but only the male remains to guard the eggs, and he leads 

 the young when they are hatched in large shoals near the 

 shore. Doras and Callichthys of the same family in South 

 America build nests of grass or leaves, sometimes placed in 

 holes in the bank of the river. The Loricariidse have similar 

 habits. Many of the Centrarchidse, the common sun-fishes of 

 the United States, are known to build nests. The gourami, 

 Osphromenus, and the paradise fish, Macropodus viridi-auratus, 

 readily breed in aquaria, the male constructing a nest of air- 

 bubbles blown with a secretion from the mouth and watching 

 over eggs and young. 



