68 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I46 



never subjected any young individual to the stresses which would 

 be expected to produce the highest intensity type of Screaming. 



11.000 



10,000 

 9,000 - 

 8.000- 

 7.000 

 6,000 

 5.000-1 

 4.000 

 3.000 i 

 2.000 



i.oooi 



1 t — " — ? ♦ 



0.2 0.4 0.6 0.8 I.O 



Fig. 16. — A single very loud Squeak, uttered by an immature. 



Based upon a spectrogram by a "Sona-graph." 

 There were at least three more harmonics with this note that are not shown 

 in the drawing. 



Patterns intermediate between pure Squeaks and pure Screams are 

 variable, but always more or less intermediate in length and sometimes 

 slightly higher in pitch, on the average, than the lowest Squeaks. They 

 also tend to fluctuate, rise and fall slightly in pitch, in much the 

 same way as pure Screams, but the number of fluctuations is less 

 than in the latter. Sometimes an intermediate pattern retains a trace 



