The principal drainage channels of the eye are herein considered as being the ocular veins which may be injected from the anterior chamber, as was done by Schwalbe,1Leber,2Gutmann,3Seidel4and many others. These veins are the anastomoses of a great network (schematically illustrated in figure 1)5which has been abstractly divided and subdivided into smaller ones. For instance, Maggiore6spoke mainly of the conjuctival plexus, the plexus of Tenon's capsule, the episcleral plexus, the deep intrascleral plexus and the canal or plexus of Schlemm. Dvorak-Theobald7failed to distinguish the plexus of Tenon's capsule described by Maggiore. She spoke mainly of the conjunctival plexus, the episcleral plexus, the intrascleral plexus, the deep scleral plexus and the canal or plexus of Schlemm. The abstract division of the great network of drainage channels into smaller ones has its advantages, and it