1877.] Traces of a Voice in Fishes. 147 
standing, while those peculiarities which distinguish them from 
each other are in most cases of later origin. If, then, we make 
a reciprocal cross, that is, if we select two allied species or varie- 
ties and cross the male of one with the female of the other, and 
then reverse the process, using the female of the first and the 
male of the second, we should expect in most cases to find a dif- 
ference in the offspring. Where the male of species A is crossed 
with the female of species B, we should expect the offspring to 
inherit from its mother the characteristics common to both par- 
ents, and from the father some of the distinctive marks of the 
Species or variety A. In the second case we should expect it to 
unite some of the features of the form B to those peculiar to the 
genus. To take a special case; if we cross a stallion with a 
female ass we should expect, according to our hypothesis, to find 
that the offspring exhibited the characteristics of the Equide, to- 
gether with some of the distinctive features of the horse, while 
we should expect to find that the offspring of the jackass and the 
mare united some of the specific features of the ass to those com- 
mon to both parents. It is needless to say that this experiment 
has been tried thousands of times with a uniform result which 
agrees perfectly with the demands of our hypothesis. In some 
cases the result of reciprocal crosses seems to directly oppose our 
conclusions, but the difficulty is in many instances only appar- 
ent. A species sometimes differs from its allies, not in having 
acquired new characteristics, but by reversion or arrest, and such 
a species will transmit its distinctive features through the female 
rather than through the male. Thus the Niata cattle, which 
Seem to be a reversion to an extinct form, are more prepotent 
over other varieties through the female than through the male, 
—— 
TRACES OF A VOICE IN FISHES. 
BY CHARLES C. ABBOTT, M. D. 
E speech be but the means of communicating emotions or in- 
tentions to other beings, even invertebrate animals possess 
faculties of the same nature. We see insects, such as ants, 
which live in so-called communities, carrying out elaborately 
preconcerted warlike undertakings and attacks. A beetle which 
in rolling the ball of dung inclosing its egg has allowed it to 
Sip into a hole from which it is unable to extricate it, flies 
away, to return in a short time with a number of assistants suffi- 
