1925] Storer: A Synopsis of the Amphibia of California 
103 
of a specimen. It may be that pacificus, which has the lowest number 
of costal folds of any member of the genus, and which has also rela- 
tively large eyes and wider head and body, is nearest the ancestral 
stock from which the “slender salamanders” have descended. Isola- 
tion upon the Channel Islands, in the absence of competition with 
other Plethodont species, may have permitted survival in a form less 
specialized than that required of the mainland stock. 
Plethodon elongatus Van Denburgh. Del Norte Salamander 
Plethodon elongatus Van Denburgli (1916, pp. 216-218). Original descrip- 
tion, type from Requa, Del Norte County, California. 
Plethodon elongatus , Grinnell and Camp (1917, p. 134, tig. 2). 
Plethodon elongatus, Stejneger and Barbour (1917, p. 15; 1923, p. 10). 
Diagnosis. — Size small among California salamanders, total length 
up to 117 millimeters (4% inches) ; naso-labial groove present; costal 
grooves 16 [costal folds 15?] ; general form slender ; coloration black- 
ish brown, with dorsal stripe of light brown, black edged; ventral 
surface sprinkled with small dots of white. 
Comparisons— Distinguished from other California salamanders 
by presence of 16 costal grooves [=15 folds?], in combination with 
well developed limbs and presence of light stripe along back; from 
Batrachoseps by better development of limbs and smaller number of 
costal folds; from Aneides and Ensatina by larger number of costal 
folds. 
Description (adapted from original description by Van Denburgh, 
1916, pp. 216-218). — Snout rounded in outline from above and in 
profile ; head somewhat depressed, width about that of widest part of 
body; external nares small, internarial space about equal to distance 
from naris to pupil ; naso-labial groove descending nearly to margin 
of lip; eyes moderate; interorbital space about 1% times length of 
orbital slit [not length of orbit as elsewhere in this paper — T. I. S.] ; 
margin of lip bent downward from end of muzzle to below eye ; 
neck a little narrower than body ; gular fold ‘ 1 continued up on side 
of neck and then forward as groove to orbit ’ ’ ; limbs a little stouter 
than in P. intermedins of Oregon ; digits 4, rather short, tips rounded, 
each with small terminal pad, in order of decreasing length, 3, 2, 4, 1, 
not webbed ; adpressed limbs separated by about 6 costal folds ; mid- 
dorsal groove present on back; costal grooves 16 [folds 15?] ; second 
toe shorter than fifth, third and fourth nearly equal ; tail cylindro- 
conic, posterior half compressed laterally, with strong vertical grooves 
nearly to tip. 
Tongue large, ovate, not emarginate, attached along median line 
but free laterally and for a short distance posteriorly ; internal nares 
small; vomerine teeth in two slightly curved series beginning just 
behind internal nares, converging obliquely backward, separated 
medially by space greater than diameter of internal naris; para- 
sphenoid teeth in one patch throughout, separated from vomerine 
teeth by interval equal to distance from [internal?] nostril to edge 
of lip. 
