No abstract

Hearing. It is often forgotten that the resonance theory of hearing first propounded by Cotugno, in 1761, was reaffirmed by Bell in 1826 ; but it was not until Helmoltz, in 1863, brought his physical insight t3 bear on these views that this theory was accepted, which has now become exclusively associated with his name.

A previously unreported pancreatic duct was found by Liu (1989) in Pekin ducks. This duct has now been consistently found in six breeds of domestic ducks and six species of wild ducks in China. For purposes of Nomina Anatomica Avium it is hereby called the 'first pancreatic duct' (Ductus pancreaticus primus) since it enters the duodenum at or near the flexure where the descending duodenum becomes the ascending duodenum. All other pancreatic ducts enter the duodenum later, closer to where it joins the jejunum. This first pancreatic duct drains the caudal extremity of the dorsal lobe of the pancreas and can be easily exteriorized for experimental purposes. Within the parenchyma of the dorsal lobe of the pancreas this duct communicates with the dorsal pancreatic duct. In the present study of the gross anatomy of the pancreatic lobes of domestic and wild Chinese ducks we describe and illustrate variations in position and number of all biliary and pancreatic ducts.

1. Experimental proof is given that Cyprinoid fish can inflate their swim bladders either by swallowing air or, far more slowly, by secreting a gas rich in oxygen, although they have no gas glands in the ordinary sense of the term. 2. Attention is directed to the high gas pressure which such fish maintain in their bladder and its probable use is discussed. 3. The anatomy of the pneumatic bulb at the oesophageal end of the pneumatic duct in Cyprinoid fishes is described.