38 Aquatic Lite 
determined which type of tail is dom1- 
nant. In any event it would seem that 
in this hybrid we have individuals that 
are dominants in this factor and reces- 
sives in the others, or vice versa. One 
writer records that in the first hybrid 
generation the individuals bearing gen- 
eral dominant characters prevail in the 
ratio 6:4. In a litter of the second hy- 
brid generation examined by the writer 
the proportion was about 5:5. The father 
was an apparent dominant, and the 
mother a recessive, the result indicating 
that the dominant was impure, or, in 
other words, carried the recessive char- 
acter. From the evidence thus far made 
available, the poecilid hybrid conforms to 
Mendel’s law, but further studies should 
be made. And in this connection it may 
be noted that we are dealing with parent 
forms in themselves variable. We have 
three or four color forms of each that 
freely interbreed. Platypoecilus macu- 
latus rubra varies to a great extent in the 
intensity of the orange or red ground 
color and in the presence or absence of 
the tiny dark spots. Further, it may or 
may not be possible to draw conclusions 
from a single litter. Contrary to the 
heretofore accepted theory, live-bearing 
fishes, or at least certain species bred by 
aquarians, will bring forth several litters 
resultant from a single intercourse with 
the male. ‘The writer once possessed a 
female of P. m. rubra that produced five 
successive litters. The specimen occu- 
pied a small aquarium alone ; hence clan- 
destine intercourse was impossible. From 
this it follows that a gravid female of. 
the first hybrid generation should be seg- 
regated immediately upon the fact be- 
coming apparent, and kept so until all the 
litters had been developed and expelled, 
and conclusions drawn from the total 
rather than from a single litter. 
The hybrid Danio does not admit of 
much discussion. ‘Too few individuals in 
proportion to the normal total were se- 
Cured ahha issan sintermediatem 
places it in contrast with the poecilid 
hybrid. If it proves fertile and repro- 
duces intermediates, it will be the third 
case in which heredity does not seem to 
follow the Mendelian rule. The two re- 
corded cases may be due to some physio- 
logical reason we do not yet understand. 
—FEditor. 
SS 
Plant Containers 
Sturdy fishes! Luxuriant plants! And 
that is the sum total of a flourishing 
aquarium. Smith says this follows as 
Smith’s Plant Containers 
the natural sequence to the use of his 
plant containers. 
Resetting an aquarium is the least in- 
teresting and most laborious task that 
falls to our lot. The work is easy 1f the 
plants are in containers. Removal is un- 
and the little sand can be 
Instead of the 
quantity of sand ordinarily necessary to 
necessary, 
drawn out by syphoning. 
anchor the plants, we have a mere sprin- 
kling to cover the bottom. One style 
covers the entire bottom, with openings 
in suitable places, so that no soil or sand 
is used other than that in which the plants 
are actually growing. This arrangement 
is especially valuable when one wants to 
go the limit in feeding young tropicals ; 
surplus food is easily removed. Ask 
Mr. Smith to tell you about them. 
