Neue experimente über die Augenstielbewegungen vonCarcinus maenas

Carcinus maenas was filmed in normal active movement. When turning actively,carcinus maenas showed optomotoric reactions. The reactions were irregular when carcinus maenas was blinded or when the environment was homogeneous.

�ber den Lautapparat von Amazonasfischen, II

Schallreaktionen bei Nachtfaltern

Numerous Noctuides and Geometrides show quite mistakable reactions upon sound stimulations ranging from 10,000 to 20,0000 vib/sec (Hertz). The lowest limit range of perception seems to lie at 40,000 up to 80,000 vib/sec. The reactions of sitting or walking animals are instant movements of flight or catalepsy. Flying animals try evasion or stop their flight at once. Sleeping animals can not be roused by sound stimulation. There are no sound reactions if both tympani are pierced. The Noctuides and Geometrides seem to perceive the supersonic echolocation cries of bats by aid of their tympanal organs.

Maulbr�ten beim Aruan�,Osteoglossum bicirrhosum undOsteoglossum ferreirai

Atemmechanismus und Kreislauf des Amazonasfisches Pirarucu

Das H�rverm�gen der Nachtschmetterlinge

An zahlreichen Exemplaren von Noctuiden, Geometriden, Notodontiden und Arctiiden wurden Reaktionen auf Schallwellen des Frequenzbereiches 15–175 kHz beobachtet, die samtlich Flucht- oder Totstellreaktionen waren und nach Haufigkeit und Intensitat ihre niedrigste Schwelle im Bereich von 40–80 kHz haben.