BREEDING HABITS OF FISK 
159 
water while tlie tail is bent; they are then straightened, and 
it is when being straiglitened that the fish is propelled. 
The movements of the pectorals and ventrals are to steady 
the fish and to elevate and depress it, while the dorsal and 
anal fins steady the body and keep it upright, like a dorsal 
and ventral keel. 
Among viviparous bony fishes are certain Cyprinodonts 
(as Anableps and Pmcilia), the eel-like Zoarces, and the 
blind-fish of the Mammoth Cave. A small family of Cali- 
fornian marine fishes, resembling the sun-fish (Pomotis), 
are called by Agassiz Emhiotocidm, from the fact that they 
bring forth their young alive. Embiotoca Jachsoni Agassiz, 
which is twenty-seven and a half centimetres (10| inches) 
long, has been known to produce nineteen young, each 
about seven and a half centimetres (3 inches) long. 
During their breeding season, many bony fishes, such as 
the stickleback, salmon, and pike, are moi'c highly colored 
than at other times, the males being especially brilliant in 
their hues. 
Order 1. Body loDg; ventral fins 
either abdominal or wanting. . . Opistliomi (Notacanthus). 
Order 2. Body long, snake-like, 
Orders of Bony Fishes. 
no ventral fins 
Avodes (Anguilla, Eel). 
Orders. Body broad; lips with 
barbels 
Nematognathi (Amiurus, Pouts). 
Order 4. Body more or less ob- 
long (in African rivers) 
ScypTiophori (Mormyrus). 
Order 5. Body usually com- 
pressed; all the bones and fins 
well developed 
TeleocepJiali (Salmo, Perca, Gadus). 
Order 6. Head and mouth very 
large; pectoral fins supported 
by slender bones 
Pediculati (Lophius, Goose-fish). 
Order 7. Gills tufted; body long 
and slender j 
LophobrancMi (Hippocampus). 
Orders. Bonesof upper and lower 
jaw united; often rounded and 
spiny j 
Plectognathi i^^ixo^on, Mola). 
