A network of blunt ended vessels lacking direct connection to the blood vascular system. These vessels collect and drain fluids and macromolecules from interstitial spaces throughout the animal. They derive from a subpopulation of endothelial cells and have walls that are much thinner than the blood carrying vessels. The walls are mostly composed of single layer of irregularly shaped endothelial cells. Lymphatic vessels are usually classified as either superficial or deep. [ GOC:cvs http://zfin.org/ZDB-PUB-120529-43 ORCiD:0000-0002-2244-7917 http://zfin.org/ZDB-PUB-130218-10 ]