PAPERS OX ZOOLOGY 293 



can not be the homologue of the cribif omi plate of mam- 

 maKan anatomy, since the olfactory nerve does not pass 

 through any portion of it. Accordingly it wonld seem 

 that the term planum tectale would more adequately 

 exjiress the function and the position of this cartilage. 



In the younger stages of Amblystoma, the antorbital 

 process and the planum tectale are far removed from 

 each other, the fonner having no association whatsoever 

 with the nasal region. During later development, how- 

 ever, the distal part of the antorbital gi*ows forward, 

 while the base of the tectale extends farther backward, 

 so that in a laiwa 34 mm. long, these structures have come 

 to lie very close to each other. During the later larval 

 period, the cornu trabeculae. which supports the anterior 

 parts of the nasal organ, extends backward toward the 

 antorbital and the tectale: and. in a laiwa at the end 

 of metamorphosis, these structures have all imited to 

 form the lateral and the posterior walls of the nasal 

 capsule. 



It is evident, therefore, that the antorbital process, al- 

 though having its origin some distance back of the nasal 

 region, is destined to become with the planum tectale, 

 the posterior wall of the nasal capsule, which is pierced 

 by a single opening, the foramen orbito-nasalis, through 

 which the branches of the fifth nerve pass to the olfactory 

 organ. 



Considerable diversity of opinion has existed in the 

 past, in regard to the homology of this cartilage bar, 

 which arises from the trabecula considerably back of the 

 nasal region, but later becomes a part of the posterior 

 waU of the nasal capsule. Throughout the literature, the 

 terms palatine cartilage and antorbital process are used 

 interchangeably in its designation, the latter possibly be- 

 ing more commonly employed: while Parker, in a series 

 of extensively illustrated papers on the skull of the 

 Anura and Urodela has employed the tenn ethmo-pala- 

 tine. Gaupp (1S93), in his work on the chondrocraninm 

 of Eana fusca. held that the antorbital process of the 

 Urodeles is homologous with the pterygoquadrate arch 

 of the Anura; and he uses the terms "Antorbitalfort- 



