The lateral, medial and ventral surfaces of the fragment have been sheared off, so that an exact identification of the bone is impossible.
"Two New Pelycosaurs from the Lower Permian of Oklahoma"
Richard C. Fox
"Interorbital breadth" was taken across the supraorbital processes, at the narrowest place, but not from the notches medial to the antorbital projections of the supraorbital processes.
"Mammals Obtained by Dr. Curt von Wedel from the Barrier Beach of Tamaulipas, Mexico"
E. Raymond Hall
The primitive membrane of the clavule forms between the copulative cells a solid partition of two membranes, but soon after the cells have become defined the medial partition becomes pierced in the centre, and then soon entirely disappears, so that the two twin cells are confounded in one single zygospore, which is due to the union of two more or less similar utricles.
"Fungi: Their Nature and Uses"
Mordecai Cubitt Cooke