THE LIFE-HISTOBY OF THE SALMON. 299 



makes a nest of floating weeds and attaches it to other 

 water-plants ; others, such as Macropodus (Paradise Fish), 

 use the buccal secretion and air bubbles to float it, and 

 in both cases keep guard over the eggs. Many of the 

 Centrarchida (the group which contains the Black Bass) 

 make nests, and so with the American Amiurus nebidosus 

 (a Gat-Fish), and in the latter case the male guards. Doras, 

 Corydoras and Callichthys of South America make nests of grass 

 and leaves, and both male and female guard. Gymnarchus of 

 the Gambia constructs a floating nest and the male guards ; 

 whilst Heterotis niloticus makes enormous nests in the swamps 

 of the same region. The curious little Antennarius fashions a 

 nest of the floating Sargassum, fixing, by aid of the same 

 secretion as in the 15-spined Stickleback, the weeds to protect 

 the eggs — which are like bunches of grapes. 



Still more curious is the habit of Rhodeus amarus, the 

 Bitterling of Europe (allied to the Dace, Chub, and Minnow), 

 the female of which with its long ovipositor inserts the eggs into 

 the mantle-cavities of Unio or Anodon, where they are duly 

 hatched and reared. Aspredo platystacus (a Cat-Fish), however, 

 is a better nurse, since the female attaches the eggs to the spongy 

 papillose surface of the abdomen ; and so are the males of the 

 Pipe-Fishes, which carry the eggs in a long groove or pouch on the 

 under surface. Moreover, as if to demonstrate the illimitability of 

 Nature's resources, the mouth and pharynx are used as brood- 

 pouches in the male Siluroids Arius, Galeichthys, and in the 

 male Osteogenissus, the females more rarely performing the 

 same functions ; and in Arius commersonii the eggs are from 

 17-18 mm. in diameter. No food occurred in the stomachs of 

 those in this condition.* Malapterurus, again, is said to shelter 

 its fry in its mouth. But these do not exhaust the remarkable 

 variations met with in Teleostean reproduction, for not a few 

 are viviparous. Thus in our own country the viviparous Blenny 

 is a familiar instance, with its large young; and the Norway 

 Haddock is another less common form, with its small embryos. 

 Abroad, the viviparous forms range from Mud- Minnows 



* A vertebrate parallel to the condition of Asterias miilleri in the rock- 

 pools at St. Andrews, the female of which carries a mass of ova over the 

 mouth. 



2 A 2 



