Epidermal thickenings called Rete ridges (or rete pegs) extend downward between dermal papillae. Rete tubular ectasia is a disorder of the rete testis characterized by multiple benign cysts. Seabirds distill seawater using countercurrent exchange in a gland with a rete mirabile. Tunas achieve regulation of body temperature by employing complex vascular structures called rete mirabile. They are juxtaposed and branched extensively to form rete mirabile. The testis cords are precursors to the rete testis. There will also be marked acanthosis with elongation and thickening of the rete ridges. This contraction helps move the spermatozoa and fluid to the rete testes. It is the counterpart of the rete testis in males. They also occur in epidermal invaginations of the plantar foot surface called rete ridges. Each WME enters the Rete network at a single root node. The carotid rete is a counter-current heat exchanging organ in some ungulates. The rete, representing the sky, functions as a star chart. However, it is a central feature of engines that use Rete networks. It features two suns, the smaller one indicating the date on the "rete"'s calendar dial.