THE BATRACHIA OF NORTH AMERICA. 215 



as well. They are unique in the presence of only one ceratobranchial, 

 jSTecturus only approaching it in this respect. In the absence of the 

 second basibranchial it agrees with Oryptobranchus, and approaches 

 the Pseudosauria, where a part of it only remains. It also agrees with 

 Oryptobranchus in the absence or confluence of the first epibranchial 

 and in the presence of the three succeeding epibranchials. 



This family is only known from North America. 



There is but one genus of this family, which is defined as follows: 



A pharyngeal slit on the side of the neck ; vomerine teeth in antero-posterior series ; 

 no scales; limbs much reduced ; digits, two or three on each foot ; prefrontal and 

 nasal bones present ; a temporal crest ; palatine bone not inclosing choanse pos- 

 teriorly ; premaxillary bones coossified Amphiuma, 



AMPHIUMA Garden. 



Smith's Correspondence of Linnaeus, i, p. 599 ; Wagler, Systema Am- 

 phib., 1830, p. 239 ; Tschudi, Batr., 1829. p. 67 ; Gray, Cat. Batr. 

 Grad. Brit. Mns., 55; Dum., Bibr., ix, p 201 ; Boulenger, Cat. 

 Batr. Grad. Brit. Mus., ed. ii, p. 82; Ryder, Proceeds. Acad. 

 Phila., 1879, p. 14 ; Cope, Proceeds. Amer. Philosoph. Soc. 

 1886, p. 442. , 



Chrijsodonia Mitchill, Medical Recorder, 1882, p. 529. 

 Sirenoides Fitz., Syst. Reptil. 1826, p. 34. 

 3Iiircrnopsi8 Fitz., I. c. ; Gray, I. c. 



The only portion of the shoulder girdle of this genus which is ossified 

 is the scapula. The coracoid cartilages of opposite sides are distinct 

 from each other, and there is a i^roduction of the precoracoid region 

 The humerus is truncate at both extremities, making its articulations 

 with cartilage only. The carpus is cartilaginous. The osseus ilium 

 is quite short and slender; it has a long superior cartilaginous portion, 

 which is attached to an equally long cartilaginous sacral rib. The 

 inferior element is an undivided plate, which is wider than long, and 

 presents au obtuse angle anteriorly. The posterior portion of each 

 is occupied by a round discoid ossification, which forms the posterior 

 border, but does uot reach either the acetabulum or its fellow. The 

 femur is rather long and has a distinct trochanter, but no head or con- 

 dyles. The articulations are cartilaginous, as is the tarsus, which is 

 also undivided. The tibia and fibula are about one-sixth the length of 

 the femur, and the fibula is a little shorter and more slender than the 

 tibia. The phalanges in both feet are well ossified. 



The general character of these parts arc described in Stanuius'Hand- 

 buch der Zoologie, but only as included in the definitions of the order 

 to which Amphiuma is referred. 



Professor Ryder demonstrated the identity of this genus and Murcen- 



0])Sis. 



The range of this genus is the Austroriparian region. It has not been 

 found west of Louisiana, nor in the Mississippi valley north of Ar- 

 kansas. It occurs in the Floridau district. 



