Volume 25, Issue 3
March 1947, pages 51-73
pp 51-56 March 1947
The responses of avian plain muscle in general resemble those of mammalian plain muscle.
Eserine has little or no potentiating effect on the action of acetylcholine.
In sodium deficient solutions, the gut elongates activity when stimulated with alternating current.
In a muscle inexcitable to nervous stimulation, alternating current produces its usual effects.
pp 57-73 March 1947
The author has described the respiratory and vocal organs ofHemidactylus flaviviridis in detail, the more important features discovered by him being as follows :-
The right and left lungs are equal ard symmetrical, with their internal cavities undivided and saccular ; the respiratory surface is developed throughout; and there are no intrapulmonary extensions of the bronchi.
The inner lining of the lungs is raised into a network of ridges, which are closer and more prominent in the anterior than in the posterior part. The ridges are mainly of three sizes. Their histology has been described in detail.
The significance of the simultaneous movements of the throat and thorax has been pointed out.
The disposition of the peritoneum in relation to lungs has been studied, and the rôle of the viscera in restrictirg the effects of the expansion or contraction of the cœlom to the part surrourdirg the lurgs has been pointed out.
Thecricoid ofHemidactylus flaviviridis differs from that ofH. garnoti in the structure of its component rings, in the absence of the processus anterior inferior and anterior superior, and in the presence of a pair of dorsal longitudinal connecting cartilages.
The number of tracheal rings varies frcm 45 to 51 and of bronchial ones from 6 to 8. Most of the former are closed. The latter are incomplete towards their inner sides.
There is no dilatation of the trachea.
The hyoid apparatus is characterized by the development of a blunt lateral limb on thecornu hyale, by the ending of thecornu hyale andcomu branchiale I ventral to the paroccipital process, and by the presence of a vestigialcornu branchiale II.
The larynx is provided with two pairs of muscles (M. compressor laryngis andM. dilatator laryngis), which are innervated by theNervas laryngens superior and theN. laryngeus inferior.
The vocal cords are present. When fully extended, they virtually separate a dorsal layngeal chamber from a ventral one.