Some observations on arteriovenous anastomosis (AVA) morphogenesis of rats were considered in this investigation. Interesting typical glomus anastomoses observed under light microscopy were determined by photography before evaluation. AVAs in the skin and mesentery were compared with those reported in morphological studies in the literature. Most of the glomus anastomoses were determined to be in conformity with those in the studies reported. Some resembled simple shunts and others complex glomus anastomoses. It is suggested that the existence of various types of anastomoses of rat fetuses during development is dependent on blood flow.