Account must also be taken of the number of lines in each page, the number of pages in each quire, of gaps or lacunae in the manuscript, and so forth.
From the Proboscidea Arsinoitherium differs broadly in skull structure, in the form of the cheek-teeth, and in the persistence of the complete dental series of forty-four without gaps or enlargement of particular teeth.
The result is, on the one hand, a clearing away of much fantastic phylogeny, on the other, an enormous reduction of the supposed gaps between groups.
In some forms other gaps (perforations) appear in the vascular tube placing the pith and cortex in communication.
The gaps in the outer tubular stele, however, are formed by the departure of aerial branch-traces, instead of leaf-traces as in the ferns.