AbstractThe morphology of the parietal shield of the Carboniferous osteolepiformMegalichthys laticepsis described. Of special note are the following features, none of which have hitherto been observed in other members of the group: each intertemporal section of the lateral‐line canal system gives off a large, backwardly directed tube which enters the posterior part of the ipsilateral parietal bone where it becomes highly ramified; anterolaterally each intertemporal bone possesses an irregularly shaped and forwardly directed projection—the frontodermosphenotic process—which is traversed by the intertemporal section of the lateral‐line canal system. In addition, evidence is offered thatMegalichthys laticepswas equipped with a paired extratemporal bone as well as a tripartite extra‐scapular series of exoskeletal elements; also, that the presence of the extratemporal bone most likely was correlated with the configuration of the subjacent part of the endocranium; and, finally, that no appreciable movement occurred between the anterior and posterior cranial