The nasals are of moderate size and in broad contact with the ethmoid, but are separated from one another medially.
"A Review of the Middle American Tree Frogs of the Genus Ptychohyla"
William E. Duellman
The nasal roof is formed by two bones situated between the eyes; the sphenoid or wedge-bone, which is connected with all other bones of the head, and the ethmoid or sieve-like bone.
"Resonance in Singing and Speaking"
Thomas Fillebrown
He correctly names and describes the bones and sutures of the cranium; notices the quadrilateral shape of the parietals, the peculiar situation and shape of the sphenoid, and the form and character of the ethmoid, malar, maxillary, and nasal bones.
"Fathers of Biology"
Charles McRae