. A text-book of animal physiology, with introductory chapters on general biology and a full treatment of reproduction ... Physiology, Comparative. THE VOICE AND SPEECH. 649 etc., take part. Most reptiles are voiceless, in the proper sense, though there are few that can not produce a sort of hissing sound, caused by the forcible emission of air through the upper respiratory passages. Frogs, as is well known, produce sounds of great variety in pitch, quality, and intensity, some species croaking so as to be heard at the distance of at least a mile. It is a matter of easy ob- servation that when
. A text-book of animal physiology, with introductory chapters on general biology and a full treatment of reproduction ... Physiology, Comparative. THE VOICE AND SPEECH. 649 etc., take part. Most reptiles are voiceless, in the proper sense, though there are few that can not produce a sort of hissing sound, caused by the forcible emission of air through the upper respiratory passages. Frogs, as is well known, produce sounds of great variety in pitch, quality, and intensity, some species croaking so as to be heard at the distance of at least a mile. It is a matter of easy ob- servation that when frogs croak the capacity of the mouth cavity is greatly increased, owing to dis- tention of resonating sacs situated at each angle of the jaws. When tree-frogs croak, their throats are greatly distended, apparently in successive waves. But it is among insects that the greatest variety of methods of producing sounds is found. In bees and flies sounds are caused by the vibration of mus- cular reeds placed in the stigmata or openings of their tracheal tubes, also by the extremely rapid vibra- tion of their wings. The death- head moth is said to force air from its sucking stomach, and thus give rise to a sound in the same way as certain fishes. In the grasshopper a noise is produced by rubbing its rough legs against the wing-cases, and in allied forms (locusts) by moving the wing-cases against one another; and in other groups different parts of the body are brought into mutual contact or rubbed or struck algainst foreign Fig. 487.—Portion of trachea or air-tube of a caterpillar (after Gegenbaur). a. epithelial-like cellular layer; b, nuclei. The air-tubes in insects are kept up by coiled cbitinous tubes, as seen above; ard, like the blood- vessels of mammals, penetrate every part of the body. Speech. It may be noticed that the differences of voices, by which we are enabled to discriminate between individuals, are much more marked during speaking than singing. This is ow
Size: 1194px × 2093px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthormillswes, bookcentury1800, bookdecade1880, bookyear1889
