OBSERVATIONS ON THE DEVELOPMENT OF THE DIGESTIVE SYSTEM AND THE FEEDING HABIT OF THE FRY OF ACIPENSER DABRY ANUS DUMERIL

The development of the digestive system of the Acipenser fry can be divided general-ly into three stages: 1. The early development stage. When the length of the fry is 12--21.5mm, theyolk sac is large, and the alimentary tract remains primitive. Then the mouth openingand four buds of barbels appear.The fry swims vertically. 2. The completion of the alimentary tract. At this stage the fry attains a length of 21.5--26mm. The mouth is active, provided with toothed jaws. The intestine, rectumand anus are finally differentiated. The fry swims in level. 3. At the completion of the digestive system. The body length of the fry attains to26. 5--30 mm. The oral cavity bears teeth, and the liver, pancreas and pyloric caeca, etc.differentiate to completion. The fry becomes bottom dwelling. The fish is typically carnivorous and bottom dwelling. The fish prefers to eat inver-tebrates, such as freshwater Oligochaetes, Chironomids, Oladocerans, Copepods, etc. Roti-fers and algae are seldom consumed. As the body length reaches 30--31. 5mm. the yolk is nearly absorbed, and the frybegins to take food