84 Aquatic Lite 
genera, and each genus may contain from 
one to five hundred kinds of species. 
The scientific name of a fish is the genus, 
as a noun, followed by the species as an 
adjective. Thus the salmon of the Atlan- 
tic is a species of the genus Salmo, and 
its name is Salmo salar, the jumping 
salmon. The Rainbow trout of Califor- 
nia is also a Salmo and its name is Salmo 
irideus. Sometimes scientific men ignor- 
Petromyzon marinus 
Sea Lamprey 
antly or carelessly name a fish which has 
If we allowed this 
So in 
already been named. 
there would be endless confusion. 
science we always take the oldest name, 
unless it has been used before for some- 
thing else. Thus the Black Bass was 
named by different men, Micropterus, 
Calliurus, Aplites, Huro and Grystes. I 
like the name Grystes best, but it 1s 
wrong. Micropterus, “little fin,” is the 
oldest, and must be used, though it has 
not much appropriateness. 
Often we find it necessary to divide an 
old genus, as we might divide a county. 
This happens when we discover some 
new and important kind of distinction. 
Thus when we found large differences in 
the skull of the Eastern Brook Trout as 
compared with the black-spotted Trout 
and Salmon of Europe and of our West- 
ern mountains, we set off the Brook 
Trout and its relatives from Salmo as a 
new genus, Salvelinus. ‘The species be- 
comes Salvelinus fontinalis instead of 
Salmo fontinalis. Such divisions arising 
from better knowledge, and changes aris- 
ing from using an older name, are com- 
mon in science. ‘They are confusing at 
first to the beginner, but to the scientific 
worker it is just as important to have the 
right name as it is to an aquarian to have 
clean water. 
In the brooks of the world are multi- 
tudes of handsome and interesting little 
fishes all worth studying, and every one 
has a scientific name of two parts, and 
meaning in Latin or Greek something 
worth remembering. 
My first aquarium studies were on the 
“Johnny Darters,” which swarm in the 
brooks of the Middle West, the most in- 
teresting to me, of all fishes, because of 
their color and forms and the many spe- 
cies. ‘There are just a hundred kinds 
known now, and probably thirty more are 
yet to be found. They are not the hardi- 
est of fishes, for they cannot stand foul 
But they are the daintiest of 
Some day 
water. 
fishes and the most inspiring. 
I may tell you more about them. | Their 
genera are Etheostoma, Boleosoma, 
Hadropterus, Poecilichthys and many 
others, and they live in the bottom of the 
little creek just back of your house, un- 
Lampetra wilderi 
Brook Lamprey 
less you live to the westward of the 
Missouri and the Rio Grande. There are 
none in the Rocky Mountain region, and 
none in the Sierras. 
(In mentioning the Lamprey, in his 
book, The Home Aquarium, Eugene 
Smith notes that “in the aquarium they 
do fairly well, if given mud or sand to 
hide in, but they will be rarely seen. I 
put two young ones into a one-gallon 
tank, and did not see them again until 
more than a year afterwards, when, re- 
