Modification of M. cricothyroideus and the Larynx in the Mormoopidae, with Reference to Amplification of High-Frequency Pulses

The laryngeal musculature and laryngeal cartilages associated with sound production and amplification in Mormoops megalophylla and Pteronotus davyi are described and compared with homologous structures in eight species of phyllos-tomatid bats. Certain specialized structures observed in the mormoopid larynges resemble a variable Helmholtz resonating amplifier. This type of amplifier is theoretically capable of 1) varying the amplitude of a constant-frequency pulse, and 2) maintaining a constant amplitude during a frequency change within a pulse.