The Nasal Structures of Adult Cetacea

Abstract

In adult cetaceans (Fig. 50, 51) only some of the embryonic cartilaginous structures of the nasal skull are preserved as cartilage. The cartilaginous tissue either ossifies to form independent skull bones, or it becomes integrated into the bony tissue of the dermal bones, or it is dissolved and resorbed. These processes are readily understood if one realizes that most of the cartilaginous anlagen play only a transitory part during embryonic development. Capable of being built up quickly and simply, the cartilaginous tissue introduces the morphogenetic processes and paves the way for the bone tissue which is slower to build up and more complicated. The particular cartilaginous nasal elements are subject to the following modifications.