63] THE NASA L ORGAN IN AMPHIBIA— IIJGGINS 63 



In other genera, both Urodele and Anuran, these same nerves pass through 

 a small foramen in the region corresponding to that in Salamandra; and 

 since nerves and their distribution may be regarded as sufficient criteria, 

 it follows that this part of the capsule is a composite of a ventral antorbital 

 and a dorsal tectale. 



In Pipa, Bufo and Rana, the pterygoid joins the side of the anterior 

 part of the cranium, this distal portion being nearly at right angles with 

 the axis of the skull. At the anterior side, a process extends forward from 

 the bend in the pterygoid, forming the postero-lateral wall of the capsule. 

 This is the lamina externa in Bufo and Hyla; and in the adult Rana, where 

 its anterior connection with the capsule has been lost, the lamina externa 

 becomes the anterior maxillary process. This anterior process, then, 

 reaching forward from the pterygoid, be it ethmo-palatine (Parker 1881) 

 or planum terminale (Gaupp, 1893) can be none other than the antorbital 

 process of the Urodeles; and it is joined either in front (Bufo and Rana) or 

 upon its ventral surface (Pipa) by two cartilages, the oblique cartilage bar 

 and the cornu trabeculae, the latter being designated the solum anterius in 

 the Phaneroglossa. 



On the basis of the nasal capsule, Epicrium is far removed from either 

 the Urodeles or the Anura; and it would appear that the grouping of the 

 recent Amphibia into three orders by M tiller (1832) is borne out by this 

 study. Anterior parts of a pterygoid reach well forward into the nasal 

 region, and although there is no continuity between the pterygoid and the 

 antorbital (which in my material has united to the more anterior parts of 

 the capsule); yet a sharp process extending from the latter toward the 

 pterygoid leads to the assumption that at one time these parts were con- 

 tinuous and that the antorbital process in Epicrium has had a pterygoidal 

 ancestry. 



CLASSIFICATION OF THE AMPHIBIA 



The earliest classification of the Amphibia did not include the extinct 

 with recent forms, largely because of the uncertainty of the systematic 

 position of the fossil forms, which were regarded by some as reptiles. It 

 was not until 1854 that Vogt stated that Archeosaurus and all the Laby- 

 rinthodontia are amphibians and not reptiles. Owen (1866) was among 

 the first to propose a classification to include both extinct and recent forms. 



Since these earlier days most Zoologists divide the class into four 

 orders: namely; the Anura, Urodela, Gymnophiona and Stegocephala. 

 There have been few variations in the subdivisions in the Anura and the 

 Gymnophiona, but with regard to the Urodeles ideas have differed greatly. 

 Some would recognize only Salamandrina and Ichthyoidea; while more 

 commonly the tendency has been to subdivide the group into Perenni- 



