Retial structures are known and play an important role in heat regulation. Elsner et al. (1966) present a photograph of a cast of the arterial brush arising from the brachial artery. It is considered probable that similar structures are also present in the tail fluke as they are in the manatee (Fawcett,1942).
The skin of the dugong is modified for life in the water to a lesser extent than in some marine mammals, particularly, as would be expected, in thosecharacteristics that contribute to the regulation of body temperature. The blubber is thinner than in most other marine mammals and there are no arterio-venous anastomoses (AVAs) in the dermis.
AVAs are very numerous in the papillary layer of the dermis in seals and are associated with thermoregulation (Bryden et al., 1978).