Abstract
A simple shape of diverticulum was recognized in all tree shrews examined. It was located about 4.0 to 5.5cm from the end of rectum. The diameter of the diverticulum was 0.25 to 0.40cm and its length was 0.7 to 1.2cm. This structure might be a primitive form of cecum. If so, the tree shrew's large intestine(4.0〜5.5cm)is much shorter than its small intestine(59〜67cm). The cecum's form has been regarded as an important index of digestive canal's inter-species evolution. A short tubular diverticulum may be a primordial form of the cecum.
