1899.] NATURAL SCIENCES OF PHILADELPHIA. 321 



frontal boues are less than the transverse diameter of the orbit, 

 while in Desmoynatkm they equal or exceed this measurement. 

 On the other hand, the parasphenoid width is greater in the present 

 species, its interorbital portion being distinctly flattened instead 

 of strongly rounded or even ridged as in Desmognathus. Conse- 

 quently a section of this region is quadrate in Leurognathus and 

 nearly triangular in Desmognathus. A strongly marked raised line 

 crosses the parasphenoid at the posterior margin of the deutigerous 

 plates and joins the periotic process on each side; this is wanting 

 or inconspicuous in Desmognathus and in any case does not reach 

 the periotic process. 



The snout is perfectly flat between the just evident canthi 

 rostrales, and the profile is straight from the posterior margin of the 

 orbits to the sharply decurved alveolar margin of the jaw, giving 

 this salamander a physiognomy very different from that of the- 

 species of Desmognathus, in which there is a strong longitudinal as 

 well as a transverse curvature to this region. The entire roof and 

 floor of the nasal chamber are closely approximated, resulting in a 

 remarkable shallowness of the passages and a similarity in the 

 form of the palate and suout. The completely coalesced pre- 

 maxillaries are broad throughout, being nowhere less than one and 

 one- half times the diameter of the nares, w^hile the breadth be- 

 tween the latter is more than twice their diameter. At the frontal 

 suture the premaxillary is truncated and overlaps the frontal, not 

 bifurcated to embrace the mesial process of the latter as in Des- 

 mognathus. The premaxillary fontanelle, so conspicuous in 

 Desmognathus and other genera of salamanders, is entirely closed, 

 its position being indicated only by a slight depression. The 

 externa] nares are small and separated by a distance of at least 

 twice their diameter. 



Extensively developed vomero-palatine bones constitute most of 

 the roof of the mouth, and as they join the premaxillary and 

 maxillaries with perfectly flush joints, the palate is given that 

 strikingly smooth, flat and unbroken appearance which suggested 

 the generic name. There is no trace of the deep median groove 

 which separates the two halves of this bone auteriorly in Desmog- 

 nathus and communicates (usually above a narrow bridge of bone) 

 with 'the premaxillary fontanelle. These bjues are united with the 

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