112 PROCEEDINGS OP THE ACADEMY OF 



and which are in strong contrast to the black of the lateral regions. The lat- 

 ter graduates into the brown of the belly. The gray dorsal band is marked by 

 a number of short divergent spots, which are in pairs and open backwards, V- 

 shaped, one to each costal interval. One specimen constitutes a color variety, 

 as I find no other points of peculiarity. It differs in being nearly black above, 

 in having the sides longitudinally streaked, and the gular region specked with 

 white ; a whitish incomplete triangle on the front and muzzle. 



Measurements (axial). 

 No. 6341. Type 9 



Inches. 



Length from snout to rictus oris '11 



" " axilla -3 



'« «' groin -866 



" " end vent 1-016 



" " " tail 1-95 



Width head behind.. -133 



" body at sacrum "133 



Length fore limb , '14 



" hind " 17 



" " foot -05 



The specimen measured is the largest ; it contained numerous eggs in the 

 oviducts, which have attained a diameter of a line, without indication of em- 

 brj'O. This size is remarkable when compared with that in the Pleurodelidae, 

 and other salamanders. As the body is little above six lines in length, the 

 number discharged at any one time must be small. The smallest specimen 

 measures "6 inch from muzzle to groin, so that it appears that this species 

 passes its metamorphosis quite early. F. Sumichrast, to whom we are in- 

 debted for this species, says of it : 

 No. 6341, 6 specimens, Orizava, Mexico, F. Sumichrast (No. 48). 

 No. 6744, 1 specimen, " " " Color var. 



DESMO ON A THID^. 



Cope, Journ. Acad. Nat. Sci. Phila. 1866, 107. 



Prefrontals and pterygoids wanting. 



Parietals not embracing frontals. 



Orbitosphenoid separated by membrane from prootic. 



Vestibule, internal wall osseous. . 



Dentigerous plates on the parasphenoid. 



Carpus and tarsus cartilaginous. 



Vertebrae opisthocoelian. 



The peculiarity of the vertebras chiefly distinguishes this family from the 

 Plethodontidas. In the only genus which represents it there are numerous 

 peculiarities, which are not found elsewhere. Should other genera be found 

 which do not possess them, the above diagnosis would probably be the proper 

 test of their family affinities. 



The distribution is confined to the eastern district of the nearctic fauna so 

 far as yet known. 



DESMOGNATHUS Baird, 



Journ. Acad. Nat. Sci. i, 282, 285. Gray, Catal. Brit. Mus. 1850, 40. 



Premaxillaries united, embracing a fontanelle ; parietal bones ossified. 

 Occipital condyles on cylindric pedestals. Temporal arising only from the 

 atlas, with a tendinous external margin and insertion ; passing freely over 

 the parietal and prootic bones. Tongue attached, except by its lateral and 

 posterior margins. Vomerine and sphenoidal teeth present. Digits distinct, 

 4—5. 



The absence of o. prefrontale does not appear to be the result of its conflu- 



[May, 



