The serial sections illustrated beyond are from an adult male of _Smilisca baudini_ (KU 89924) having a snout-vent length of 53.0 mm. and a head width (measured at angle of jaws) of 17.0 mm. The specimen was collected 5.2 kilometers east-southeast of Cordoba, Veracruz, Mexico. Transverse sections were cut at thicknesses of 10 and 15 microns on a rotary microtome and stained according to the technique described by Baldauf (1958). Cleared and stained specimens and dried skeletons also were used. Figure 1 is based on KU 68183-4 and Fig. 9 on KU 55614. All other drawings are made from KU 89924. In all cross-sectional figures, bone is represented by solid black, cartilage by stippling, and connective tissue by cross-hatching. Unless otherwise noted all descriptions are given in an anterior-posterior sequence. Commonly accepted English terms are used. For example, dentary is used in preference to dentale and maxillary process instead of processus maxillaris. If no commonly accepted English term is available for a given structure, the Latin name is retained. For example, the cartilaginous plate separating the cavum principale from the cavum medium is termed the lamina superior. [Illustration: FIG. 1. Partially disarticulated skull (left frontoparietal and nasal removed) of _Smilisca baudini_, KU 68183, [Female] x 4. Abbreviations: _al. proc._, alary process of premaxillary; _ant. sq._, anterior arm of squamosal; _epi. em._, epiotic eminence; _exocc._, exoccipital; _fpar._, frontoparietal; _fpar. fon._, frontoparietal fontanelle; _max._, maxillary; _nas._, nasal; _pal._, palatine; _pal. proc._, palatine process; _pasph._, parasphenoid; _pmax._, premaxillary; _pvom._, prevomer; _post, sq._, posterior arm of squamosal; _pro._, prootic; _pter._, pterygoid; _qj._, quadratojugal; _spmax._, septomaxillary; _sept, nas._, septum nasi; _spheth._, spnenethmoid; _vent, sq._, ventral arm of squamosal.] DESCRIPTION OF INTERNAL CRANIAL OSTEOLOGY Olfactory Region _Alary cartilage._--The anterior end of the alary cartilage (_al. c._, Figs. 2-5) lies within the posterior concavity of the alary process (_al. proc._, Figs. 1-3) of the premaxillary (_pmax._). In posterior sections the cartilage assumes a dorsolateral position (Fig. 3), ventral and slightly lateral to the tectum nasi. The alary cartilage remains narrowly separated from the tectum nasi but fuses ventromedially with the septum nasi and forms a nearly complete cartilaginous capsule around the anterior end of the cavum principale. Posterior to the anterior end of the cavum medium and the lamina superior, the alary cartilage separates ventrally from the lamina. In subsequent posterior sections, the cartilage, arcuate in cross section, becomes progressively smaller and terminates at the level of the union of the medial and lateral recesses of the cavum inferior.