Olfactory bulbs. In squamates, the frontal(s) has a pair of subolfactory process (=parolfactory bulb recess) that may or may not fuse along the midline, depending on the species. The processes suture in many Varanus species. There are descriptions and codings for this character in "Assembling the Squamate tree of life" by Gauthier et al.

If the subolfactory process is the same thing as ventrolateral process (see the attached image 1), than I think that parolfactory bulb recess is not the subolfactory process. I guess that paired parolfactory bulb recesses should be the depressions on the medial sides of ventrolateral processes that indicates olfactory bulb.

But than there should be the space between the olfactory bulb and frontal? (image 3) What for?

My drawings of frontal sections are correct?

In mosasaurs olfactory canal not embraced ventrally by ventrolateral processes (0); or canal almost or completely enclosed below (1) (Image 2)

I hope that I have correctly stated my point!

Thanks for the Gauthier et al. paper!

I agree - the subolfactory process is posterior to the recess. Now I'm a little hesitated to assume that the whole region is occupied by olfactory bulbs: if so, those are large. There are similar but shallower recess in some anguimorphs (and maybe lizards in general). I have seen it in digimorph--can't remember which one.

Here's a CT of a live female Komodo. It's the best you'll find for an extant model.

Kent

Thank you, Richard!

And which program I should use to observe this CT model?

Anything that runs dicom. I use Dicomworks- a free download, for only $25 you get a permanent license with all the bells and whistles. If you have MAC, use Osirix. The study was a clinical zoo case in California. Poor baby had bade spinal stenosis and the craniocervical junction. The slice thickness is thicker than we'd do these days but it's pretty clear in soft tissue windows that the bulbs are much smaller than the olfactory antrum and end @ the proximal margin of the cribriform plate/groove. I think paleo reconstruction of olfactory bulbs are generally always bigger than the soft tissue anatomy.