1883.] The Mink or Hoosier Frog. 949 
seen the bull-frog open his mouth and scream for over a minute, 
like a child in distress, 
8. When they give their note it is always produced by inflating 
the throat pouch and suddenly expelling the air, whereas in R. ` 
- halecina there is a pouch near the angle of the jaws, on either 
side. 
9. They are all tinged, more or less, with yellowish-green on 
the chin, which soon shades towards the throat and breast, and 
on the belly is white, more or less, in many subjects most beau- 
tifully so. 
There is thus an analogy in their life-history, and in their ex- 
ternal conformation that at once forms them into a group by them- 
selves, and makes a marked section. I am not aware, however, 
that there is any anatomical difference sufficient to make a 
genus. In fact I may be allowed to remark that anatomical 
variations are more frequent among the Batrachia than among 
any other class of the animal kingdom. There are species that 
even produce the ova fully fertilized, viz., the Siredon genus, be- 
fore the larva is perfect. The bones in the feet of some species 
are never fully developed, and in others, closely allied, the bones 
are perfectly formed. But this is a subject in itself, on which 
much can be written, and at best such a subject can only end in 
theory and personal ideas. 
The love notes of the Ranidæ, admirably termed “chant 
amour ” by the French, is a point in their history I have seldom 
or never seen noticed in American works, and is a peculiar feature 
in this “ /ife-history” that most emphatically marks whole sections. 
If I hear the notes of a frog, I can tell to what class it belongs, 
and when to expect its spawning season. On the 24th of June I 
collected a number of R. septentrionalis and placed them in a large, 
white, earthen vase. They remained quiet for a time, and I put 
in some chips and a quantity of Ranunculus. Next morning 
three couples were paired and lying at the bottom of the vase, 
and secreted among the Ranunculus. One pair were on the sur- 
face, but the female had been injured. It thus seems they accou- 
ple in the night, and immediately sink and hide. Occasionally 
there was a trivial chant amour from the last pair, evidently so 
given, but the others were mute. The R. halecina may often be 
heard croaking its lugubrious and dismal love notes from the bot- 
tom of some muddy ditch. That of the mink frog is a rapid 
