Abstract: Being one of the two existing species of the subfamily Iniinae,the white-flagdolphin,Lipotes vexillifer Miller is a rare animal and wvas originally recorded onlyin the Tung-Ting Lake and in the adjacent parts of the Yangtze River.Only a fewspecimens have been preserved in the museums of our country and still scantierabroad.Four adults of this dolphin,taken from the Yangtze River in the vicinity of O-cheng and Hung-hu,have recently been donated to the Institute.Two of them arepregnant females,and upon dissection two embryos of advanced stage have beenobtained.This paper deals with certain external characteristics of this species as well asthe results of observation on the skeleton and the respiratory,digestive and urogen-ital organs.It makes up a needful supplement to the various comments made byprevious authors since the first description of this dolphin in 1918.