16 ILLINOIS BIOLOGICAL MONOGRAPHS [16 



From the ventral surface of the anterior cupola (c), a small prenasal 

 process arises near the foramen nasalis internus and extends downward a 

 short distance into the enveloping tissue. The antorbital processes (pa) 

 are much as before, but as yet do not meet the anterior part of the floor of 

 the capsule. 



There are some resemblances between the nasal capsules of the last 

 larval Amblystoma (Fig. 9), and the third stage of Salamandra (Fig. 13). 

 In both the planum basale and verticale are greatly reduced and the olfac- 

 tory organs lie well anterior to the forebrain. Complete chondrification of 

 the verticale in Salamandra has obliterated the fenestra ethmoidalis, so that 

 internasal space and cavum cranii are no longer continuous. The anterior 

 cephalic process (ce p) of the verticale is cylindrical and more elongate than 

 before and extends forward nearly to the level of the base of the prenasal 

 process. I have not observed this structure in any other Urodele. 



Each antorbital process has grown forward beneath the lateral margin 

 of the tectale, and has united to the caudal extension of the cornu, thus 

 outlining two large fenestrae. Of these, the largest lies in the floor of the 

 capsule and surrounds the choana; while the orbito-nasal foramen (fon) 

 is posterior and lies between the posterior margin of the tectale and the 

 processus antorbitalis. In this stage the lateral margin of the tectale has 

 not united to the antorbital process, although they lie very close, so that no 

 fenestra infra-conchalis exists; but Jacobson's organ lies between these 

 parts as in Amblystoma. 



The anterior dorsal surface of the tectale is pierced by four foramina, 

 the medial three of which conduct rami of the nasalis internus of the pro- 

 fundus nerve from the capsule; its main branch passing to the foramen 

 nasalis internus at the base of the prenasal process. The lateral and larger 

 gap represents in Salamandra the beginning of resorption, which has been 

 described in a corresponding stage of Amblystoma. Posteriorly the tectale 

 is pierced by a small foramen for a branch of the profundus. 



This stage of Salamandra is very similar to the last larval stage of 

 Amblystoma, and also represents the culmination of larval development. 

 Resorption has begun and the capsule of the adult would probably be 

 conspicuously reduced by the growth of the covering bones. Salamandra 

 differs from Amblystoma in the complete separation of the tectale from the 

 antorbital, and the consequent absence of the fenestra infra-conchalis; 

 however the approximation of these parts would suggest their connection 

 in the adult. The ethmo-palatine of Parker is the antorbital process, and 

 he says that in the adult it is very likely to fuse with the anterior parts of 

 the capsule. Furthermore Parker has described in the adult the persistence 

 of the prenasal processes and the median rostrum, and says that they seem 

 to be the non-segmented rudiments of the paired and unpaired elements of 

 the foremost visceral arch, whose splints are the premaxillaries. This 



