Concatenatable lighting fixtures, each comprising a unitary cover member having a circuit board mounting platform integrally formed with suitable heat sinking and which mounts onto a cooperating base chassis. In one embodiment, the circuit board mounting platform extends farther from one end of the cover member than the other so as to facilitate placement of LEDs in a fashion which enhances lighting uniformity and minimizes dark spots. In one embodiment, first and second guide members may be positioned in respective opposite ends of adjacent fixtures, each guide member having a plurality of extending fingers with a flexible electrical conductor-carrying conduit disposed between the respective opposite ends and retained in position by the fingers.