sancta_, inferior in sacred interest only to that rock-hewn sepulchre consecrated evermore by the body of Our Lord. These reflections will lend to the study of the Catacombs an interest of the highest and intensest character. It is impossible to discover with exactness the extent of this vast necropolis on account of the number and intricacy of its tangled passages. That extent has been greatly exaggerated, however, by the monkish _ciceroni_, who guide visitors through these subterranean labyrinths.[5] There are some forty-two of these cemeteries in all now known, many of which are only partially accessible. Signor Michele De 15 Rossi, from an accurate survey of the Catacomb of Callixtus, computes the entire length of all the passages to be eight hundred and seventy-six thousand _mètres_, or five hundred and eighty-seven geographical miles, equal to the entire length of Italy, from Ætna’s fires to the Alpine snows. The entrance to the abandoned Catacomb is sometimes a low-browed aperture like a fox’s burrow, almost concealed by long and tangled grass, and overshadowed by the melancholy cypress or gray-leaved ilex. Sometimes an ancient arch can be discerned, as at the Catacomb of St. Priscilla,[6] or the remains of the chamber for the celebration of the festivals of the martyrs, as at the entrance of the Cemetery of St. Domitilla. In a few instances it is through the crypts of an ancient basilica, as at St. Sebastian, and sometimes a little shrine or oratory covers the descent, as at St. Agnes,[7] St. Helena,[8] and St. Cyriaca. In all cases there is a stairway, often long and steep, crumbling with time and worn with the feet of pious generations. The following illustration shows the entrance to the Catacomb of St. Prætextatus on the Appian Way, trodden in the primitive ages by the early martyrs and confessors, or perhaps by the armed soldiery of the oppressors, hunting to earth the persecuted flock of Christ. Here, too, in mediæval times, the martial clang of the armed knight may have awaked unwonted echoes among the hollow arches, or the gliding 16 footstep of the sandaled monk scarce disturbed the silence as he passed. In later times pilgrims from every land have visited, with pious reverence or idle curiosity, this early shrine of the Christian faith. [Illustration: Fig. 2.--Entrance to St. Prætextatus.]