A skull mountable,implantable percutaneous fluid delivery device (2; 52; 82; 02) is described for use in delivering fluids to target sites in the brain. The device (2; 52; 82; 102) includes a subcutaneous base portion (6; 56; 86) comprising one or more ports for supplying fluid to one or more implanted catheter devices (18). A percutaneous portion (4; 54; 84; 104) of the device comprises an extracorporeal surface (10), the one or more ports of the subcutaneous base portion (6; 56; 86; 106) being accessible from the extracorporeal surface (10) of the percutaneous portion(4; 54; 84; 104). The subcutaneous base portion (6; 56; 86) is at least partially insertable into a complementary recess formed in a bone (44; 140) and comprises one or more anchoring features comprising at least one radially protruding wing (24; 62; 88; 124) for directly anchoring the subcutaneous base portion (6; 56; 86;106) to the bone (44; 140).