The nasal bones, which form the roof the snout, bear a pair of enlarged bosses of bone as in other cryptodontians.
In contrast to the small, oval-shaped, relatively narrow, and smooth-textured bosses of Tropidostoma, the roughened bosses of Bulbasaurus are very large and nearly form a single continuous boss (although a narrow strip of the premaxilla extends backwards between the bosses).
Aulacephalodon and Pelanomodon also have large and roughened bosses, but they are separated in part by the nasals.
At the back of the bosses, a slight indentation wrapping around the top and sides of the skull separates them from the eye socket, typical of cryptodontians except for Odontocyclops.
The suture between the nasals and the frontal bones is slightly raised relative to the rest of the skull; the same raised suture is also seen in Aulacephalodon and Pelanomodon.

Typical of geikiids, the interorbital region between the eyes was quite broad.
The lacrimal bones, prefrontal bones, frontal bones, and jugal bones form the margin of the eye socket, with the portion comprised by the lacrimals having an orbital ridge that is better-developed and more raised.
Unlike other cryptodontians, there is no evidence of a second set of bosses on the prefrontals, although their surfaces are somewhat thickened.
A relatively deep midline depression (mildly developed in Tropidostoma and Oudenodon, but absent in other geikiids) is visible on the frontals, which are situated largely between the eyes and form roughened edges where they contributes to the rims of the eye sockets.
There appears to be no separation of the postfrontal bones from the frontals, which is probably an adult characteristic as in Aulacephalodon.
The elongate jugals form part of the zygoma, or bony cheek, and ends at the temporal fenestra.
It also forms part of the temporal and postorbital bars; Pelanomodon differs from Bulbasaurus in having small bosses on the latter portions of the jugals.
The nasal bones, which form the roof the snout, bear a pair of enlarged bosses of bone as in other cryptodontians. In contrast to the small, oval-shaped, relatively narrow, and smooth-textured bosses of Tropidostoma, the roughened bosses of Bulbasaurus are very large and nearly form a single continuous boss (although a narrow strip of the premaxilla extends backwards between the bosses). Aulacephalodon and Pelanomodon also have large and roughened bosses, but they are separated in part by the nasals. At the back of the bosses, a slight indentation wrapping around the top and sides of the skull separates them from the eye socket, typical of cryptodontians except for Odontocyclops. The suture between the nasals and the frontal bones is slightly raised relative to the rest of the skull; the same raised suture is also seen in Aulacephalodon and Pelanomodon.
Typical of geikiids, the interorbital region between the eyes was quite broad. The lacrimal bones, prefrontal bones, frontal bones, and jugal bones form the margin of the eye socket, with the portion comprised by the lacrimals having an orbital ridge that is better-developed and more raised. Unlike other cryptodontians, there is no evidence of a second set of bosses on the prefrontals, although their surfaces are somewhat thickened. A relatively deep midline depression (mildly developed in Tropidostoma and Oudenodon, but absent in other geikiids) is visible on the frontals, which are situated largely between the eyes and form roughened edges where they contributes to the rims of the eye sockets. There appears to be no separation of the postfrontal bones from the frontals, which is probably an adult characteristic as in Aulacephalodon. The elongate jugals form part of the zygoma, or bony cheek, and ends at the temporal fenestra. It also forms part of the temporal and postorbital bars; Pelanomodon differs from Bulbasaurus in having small bosses on the latter portions of the jugals.
Bulbasaurus