The most important men in this school after Borelli were Nicolaus Stensen (Steno), (1638-1686), Giorgio Baglivi (1669-1707) and Lorenzo Bellini (1643-1704).
Successive observers in Italy, notably Fracastoro (1483-1553), Fabio Colonna (1567-1640 or 1650) and Nicolaus Steno (1638 - c. 1687), a Danish anatomist, professor in Padua, advanced the still embryonic science and set forth the principle of comparison of fossil with living forms. Near the end of the 17th century Martin Lister (1638-1712), examining the Mesozoic shell types of England, recognized the great similarity as well as the differences between these and modern species, and insisted on the need of close comparison of fossil and living shells, yet he clung to the old view that fossils were sports of nature.
NICOLAUS STENO (1631-1686), Danish naturalist, was born at Copenhagen in 1631, and studied medicine and anatomy in that city and in Paris.
In this notable work Steno described various gems, minerals and petrif actions (fossils) enclosed within solid rocks.
Many other allied genera, such as Prodelphinus, Steno, Lagenorhynchus, &c., are also included in the family Delphinidae, some of which live wholly in rivers.