Cope.] *±^ [Feb. 5, 



On the Structure and Affinities of Hie Amphiumidm. By E. D. Cope. 

 {Read before the American Philosophical Society, February 5, 1SS6.) 



By all authors, the genus Amphiuma has been included in the same 

 family division with Protonopsis and Megalobatrachus until 1866. At that 

 time the writer of this paper proposed to separate it from the latter genera 

 as the type of a family Amphiuniidre, while the other genera were placed 

 in another family with the name Protonopsidse. This course has not been 

 followed by later writers ; in the Catalogue of the British Museum by Dr. 

 Boulenger (1882), for instance, the three genera being included in one 

 family, the Amphiumidse. 



The reasons for keeping the Amphiuniidse distinct from the Protonop- 

 sidae were stated to be the following :* 



Amphiumidm: "An axial cranial bone ('? vomer) in front of orbito 

 sphenoids, and one forming palatal surface in front of parasphenoid. * 

 Parietals prolonged laterally, not reaching prefrontals. Vestibule, wall 

 osseous internally. Premaxillaries consolidated. Occipital condyles on 

 cylindrical pedestal." 



Protonopsidm : "No anterior axial cranial bone. * * Parietals and 

 prefrontals prolonged, meeting and embracing frontals. Wall of vestibule 

 membranous internally. Premaxillaries separated. Occipital condyles 

 sessile." 



The following observations were made on the Amphiuniidse: "The 

 occipital condyles and temporocervical tendon are quite as in Desmogna- 

 thus ; they have not been previously described, f In Amphiuma means 

 there is a minute not articulated bone on the suture between the o. o. 

 frontalia and prefontalia in the situation of the lachrymal. There are 

 some approximations to Caecilia in Amphiumidre. It does not appear to 

 have been noticed that the * * free margin cf the frontal seems to fore- 

 shadow the overroofing of the orbit and temporal fossa seen in Caecilia. 

 There is also a very large foramen or canal passing through the o. maxil- 

 lare from near its middle to the orbit, foreshadowing the canalis tentacu- 

 liferus of Ca'cilia : a narrow one occurs in the same situation in Proto- 

 nopsis. Further the prominent horizontal anterior inferior processes of 

 the vertebral centra are the same in Amphiuma and Concilia." 



Occasion for the revision of these views having presented, the following 

 facts and conclusions have been reached. 



The characters assigned as above to the two families Ampiriumidse and 

 Protonopsidse are abundantly sufficient for retaining them as distinct. The 

 form of the occipital condyles might be excepted from this estimate, and 

 the axial bone in front of the parasphenoid proves to be abnormally cut 

 off in the specimen then examined. The Protonopsidse agree with other 



* Journal Academy Philadelphia, 1866, p. 101. 



t They were described by Dr. J. G. Fischer, Anatomisch. Abhandl. ub. Peren- 

 nibrunch. u. JHrotrein. Erstes lleft, p. 01 1S01. 



