130 Journal of Comparative Neurology 



connect on the lateral aspect of the olfactory cavity. (See Fig. 

 7, Plate V, in. ) The external nares are bounded in front by the 

 incurved anterior cornu, and above and below by the dorsal and 

 ventral cornua of the internasal plate. 



The pre-maxillaty, seen in cross section (in, Figs, i-io, Plate 

 V), sends a process backward over the internasal and overlap- 

 ping for a short distance the frontals, (see fix, Figs. 5-10, Plate 

 V). The nasal processes of the pre-maxillary meet in the mid- 

 dle line through almost their whole extent, in this type, so that 

 the internasal cartilage is not visible from above, and the mem- 

 branous space which in other examples exists in front of the 

 cartilage, is reduced to a fissure. This bone does not, as in 

 Axolotl, surround the olfactory cavity upon its external aspect, 

 but seems to be pushed dorsad and above, its lateral investing 

 function being usurped by the large maxillary seen at mx, Figs. 

 7-15, Plate V. 



The premaxillaries do not develop a palatal plate, but the 

 maxillaries, which are very much lengthened backwards toward 

 the mandibular articulation, have an inturned edge which Parker 

 describes as a rudumentary platal plate. The maxillaries have 

 also a short nasal process extending dorsad and backwards. (See 

 Figs. 9, 10, 11, Plate V.) 



The naso-lachrymal, as seen in Fig. 19, Plate V, nl, just 

 after it emerges from the general cavity of the nose, is found 

 lying encased on three sides by the maxillary ; and by two 

 small processes of the nasal, forming tor a short distance a slight 

 groove in which it rests. This complete envelopment in the 

 investing cartilages is well shown under a higher power in Fig. 

 5, Plate VI. This position it retains until it approximates the 

 surface of the head, when it lies in a slight depression in the 

 nasal. Finally as it bifurcates on its approach to the eye (Figs. 

 13-15, Plate V, nl) it lies entirely free just beneath the surface 

 of the skin. 



The frontals are seen in Figs. 5-15, Plate V, at/. Each 

 frontal is overlapped by the nasal process of the pre-maxillary, 

 (px, Figs. 5-10,) by the nasal (Figs. 13-15, n) and by the ect- 

 ethmoid (not shown in figures, lying as it does farther caudad). 



