This article presents accounts of two patients with cholesteatoma of the tympanic part of the temporal bone, located immediately lateral to the tympanic annulus (and with an intact tympanic membrane). The lesions were located deep in the anterior and inferior walls of the canal, especially in the vaginal process of the tympanic part. These more severe cases required surgical correction (removal...

The indications for myringoplasty in children has always been a controversial subject since many authors feel the high frequency of the phlogistic auricular processes in children constitute an unfavorable prognostic factor to success of the procedure. The authors present the results obtained in 23 patients under 17 years of age who had undergone myringoplasty for simple perforation of the tympa...

Physical mechanisms involved in directional hearing are investigated in two species of short-horned grasshoppers that differ in body length by a factor of 3­4. The directional cues (the effects of the direction of sound incidence on the amplitude and phase angle of the sounds at the ears) are more pronounced in the larger animal, but the scaling is not simple. At high frequencies (10­20...

Potamitesflavogularis sp. nov. is described from the Napo and Tungurahua Provinces around 1800 m elevation in eastern Ecuador. The new species is closely related, sibling, and sympatric to Potamites cochranae to which it has been previously confused. It is characterized by the absence of isolated basal flounces of spines and presence of calcareous spinules on flounces of the hemipenis, a short ...

Muskoxen (Ovibos moschatus) are large (>200 kg adult body mass) mammalian herbivores that overwinter in the polar regions. Calves are around one-third the body mass of mature females and may be expected to suffer greater thermal stresses in winter compared with adults because the ratio of surface area to volume (SA:vol) is much greater for calves than for adults. We found that during feeding bo...

One of the fundamental problems in auditory research is the origin of the frequency selectivity of auditory receptors. Horridge (1960) demonstrated that the auditory interneuroneS in locusts were tuned to different sound frequencies, thus suggesting that the auditory receptors were frequency selective. Michelsen (1968, 1971) established that the auditory organ of locusts contained four groups o...

A new frog of the genus Pristimantis is named and described from the summit of Abakapá-tepui in the Chimantd massif, south-eastern Venezuela. The new species is known from two adult specimens and is the second craugastorid species described from this massif. It can be readily distinguished from all congeners inhabiting the highlands of the Guiana Shield by the unique combination of the followin...

In the auditory system of bushcrickets, sound can reach the receptors via two different paths: (i) by acting on the outside of the tympana situated on both sides of each foreleg or (ii) through the acoustic trachea that opens at a spiracle on the thorax. While the spiracle is considered to be the main point of sound entry for higher audio and ultrasonic frequencies, the role of the tympana is s...

Phylogeographic structure is a product of a species’ life history and dispersal patterns, geographic history, climatic history and chance. Comparative phylogeography, using carefully chosen model species, can highlight the relative contribution of each of these factors and identify common processes affecting communities. In this study we compare and contrast fine-scale phylogeographic patterns ...

Small animals typically localize sound sources by means of complex internal connections and baffles that effectively increase time or intensity differences between the two ears. However, some miniature acoustic species achieve directional hearing without such devices, indicating that other mechanisms have evolved. Using 3D laser vibrometry to measure tympanum deflection, we show that female les...