MEXICAN AMPHIBIANS—TAYLOR AND SMITH 581 
Arms short, the digits dilated to a little more than half the diam- 
eter of tympanum, and with transverse terminal grooves; first finger 
distinctly shorter than second; practically no trace of a web except 
between the bases of first two fingers, but distinct lateral fringes on the 
distal part of outer side of first finger, medial sides of second and third, 
and on both sides of fourth, to their bases. 
A large, median, semidivided palmar tubercle, and a narrow, elon- 
gate, inner palmar tubercle at base of first finger; subarticular tuber- 
cles large; supernumerary tubercles variable in size; a tubercular ridge 
under arm. Legs long, the tibiotarsal articulation reaching beyond 
tip of snout; toes between one-third and one-half webbed, the webs ex- 
tending as fringes to the dilated tips; a strongly elevated, inner 
metatarsal tubercle; a small indistinct outer; a broad, almost flaplike 
tarsal fold extending four fifths the length of tarsus (or more); sub- 
articular tubercles normal; no trace of supernumerary tubercles; 
heels overlap two or three millimeters when legs are folded at right 
angles to body. 
Color and markings —Generally olive-gray to brownish gray. A 
broad, light brown, interorbital bar, bordered behind with darker 
color and with two dim median light spots on occiput, one behind the 
other; sides lighter, showing dark spotting or marbling; barring on legs 
almost obsolete; below creamy white, with some indistinct pigmenta- 
tion on chin and anterior part of thigh. 
Measurements in mm.—Snout to vent, 51; length of head, 21; 
width of head, 22; arm, 30; leg, 85; tibia, 28; foot, 37. 
Variation.—Some of the younger paratypes show the color pattern 
more strongly. These have the upper lip, to some extent the lower 
also, with three or four dark bars or spots. The tympanum in the 
males is about two-thirds the diameter of the eye. 
Relationships——The species is apparently most closely related to 
Eleutherodactylus vocalis, occurring on the edge of the plateau in 
Michoacdin. Itdifferschiefly inthe absence of the vocal sac (and vocal 
slits); greater amount of webbing on feet; smaller pads in proportion 
to the tympanum; smaller eye in proportion to snout length; the 
longer tarsal fold, and its much greater development; the longer hind- 
legs, with overlapping heels; and the choanae directed more backward 
owing to the elevation of the anteriorrim. Other differences obtain. 
Three other Mexican forms of this section of the genus are known in 
México: Hleutherodactylus rugulosus in Oaxaca and Chiapas, E. natator 
in Veracruz, and LH. vocalis in Michoacan. 
Genus SYRRHOPHUS Cope, 1878 
SYRRHOPHUS PIPILANS Taylor 
Syrrhophus pipilans Tayuor, Proc. Biol. Soc. Washington, vol. 53, Oct. 7, 1940d, 
pp. 95-98, pl. 1 (9 miles south of Mazatla4n, Guerrero). 
