Abstract: Modular constructions and connector assemblies therefore. The modular construction comprises a plurality of spode units with elongated key members extending between the spode units and interconnected to form a modular framework. Adapter collars and retaining collars are employed to connect the key members to the spode units to carry torsional and longitudinal stress. In one embodiment, the spode units include union joints having a plurality of spaced slots which are adapted to receive conforming projecting lugs on the adapter collars. The slots and lugs are symmetrically located so that the adapter collar and key member can be connected to the spode unit in a plurality of angularly displaced relationships. The key member-spode unit structure may be provided with a cover tube so that the structure will carry or transmit fluid.