The two fortifications, which I propose to describe are together unique in the history of military architecture. They are very like each other, but nothing else like them exists. The first of them, Euryalus at Syracuse, has been carefully planned and published by a professional engineer, Signore Luigi Mauceri, in an excellent monograph (Il Castello Eurialo, Roma, 1928) ; but this is difficult to procure-I only know of it, and have seen it, thanks to the kindness of Sig. Dott. Giacomo Caputo, of the Syracuse museum-and there is no other adequate description of the place, though no doubt Pauly-Wissowa's article on Syracuse will contain one when it appears. Moreover, in examining the remains I seemed to see evidences of afterthoughts and changes of plan which Sig. Mauceri has missed or interpreted in ways that I find hard to accept; and therefore, though my hasty inspection and rough plans are far inferior to his careful and skilful work, it ma be worth while to place my surmises on record.