Only the briefest possible mention may here be made of those anatomists who, following immediately in the footsteps of the three great leaders mentioned above, played parts of greater or less importance in building up the science of anatomy. Each one of them did creditable work in correcting the errors made by their predecessors or in supplying descriptions of structures or structural relations which these pioneers had overlooked. Thus, long before the sixteenth century came to an end, the gross anatomy of the human being had attained a large measure of the completeness which it possesses to-day. The names of some of the more prominent men among those to whom I have just referred are the following: Giovanni Filippo Ingrassia, Matthaeus Realdus Columbus, Julius Caesar Arantius, Constantius Varolius, Volcher Koyter and Hieronymus Fabricius ab Acquapendente. Ingrassia (1510–1580), a Sicilian physician, cultivated osteology assiduously, and is entitled to special credit for having first described the stapes, the third one of the ossicles of hearing, and for having made valuable contributions to our knowledge of epidemic diseases. He was a professor in the University of Naples, and, after the year 1563, held the position of Archiater in Palermo, Sicily. His descriptions of the different bones of the skeleton were made with such care and thoroughness that later anatomists found very little for them to discover or to alter. Matthaeus Realdus Columbus (or simply Realdus Columbus), who died in 1559, was born in Cremona, Northern Italy. He served for some time as Prosector to Vesalius at Padua, and then succeeded him in the Chair of Anatomy, first at Padua and afterward at Pisa. The last teaching position which he held was that of Professor of Anatomy in Rome, in which city he counted Michael Angelo among his intimate friends. The discoveries which he made in anatomy were quite numerous and of considerable importance, and his descriptions were distinguished by an unusual degree of accuracy and clearness. Unfortunately, he did not hesitate, at the same time, to exalt the value of his own work by disparaging that of his famous teacher. Arantius, who also was one of the pupils of Vesalius, occupied the Chair of Anatomy in his native city of Bologna during the latter half of the century. His death occurred in 1589. The particular department in which he gained considerable fame was that of the foetus, the placenta, the uterus, etc. His descriptions of these structures are written with very great care. Blumenbach gives him credit for having been the first anatomist to furnish a description of the pregnant uterus in its different stages. His earliest published work bears the title “_De humano foetu opusculum_” Rome, 1564.