Rana sphenocephala 421 



tions or reticulations of the groin. The posterior faces of the thighs in R. 

 pipiens have the brown spots more or less separate and the lighter interspaces 

 are equally emphasized to form the reticulum but in R. sphenocephala the 

 brown spots become connected and surround the lighter inter-spaces, the dark 

 being the reticulum. The stripe from the snout under the eye to the shoulder 

 is yellowish, much lighter and more prominent than a similar more or less 

 bronzy line in R. pipiens. The same difference obtains in the color of the 

 lateral fold. On the upper jaw of R. pipiens there is a more or less sharply 

 defined dark line below the above light stripes and below the dark line a clear 

 white or yellowish white edge to the upper lip. In R. sphenocephala these two 

 areas are not sharp and the upper and lower lips are more or less dark and 

 light spotted. In R. pipiens the lower lip is usually with a few or no dark 

 spots while in i?. sphenocephala this is the regular coloration. On the throat 

 region and under side of the hind legs dusky fleckings much more frequently 

 enter in the coloration of R. sphenocephala than in R. pipiens. The under 

 parts are whitish or yellowish white. 



In most of the specimens the clear cut distinct white spot in the middle of 

 the tympanum is sufficiently distinctive but in some young and adults the 

 character fails to separate R. sphenocephala from R. pipiens. Our specimens 

 have not the tibia with complete cross bars but we question its use as a con- 

 stant distinction because many R. pipiens are without complete bars though 

 this latter species inclines more towards the barred state of affairs. 



If time were at hand to study as carefully 192 1 and 1922 material possibly 

 some of these foregoing distinctions made in 19 13 would be changed or 

 recognized as non-distinctive. 



STRUCTURAL CHARACTERS (WRITTEN IN 191 2) 

 On the basis of our 191 2 specimens these characters are noted. The skin 

 is smooth; on either side of the back is a prominent dorso-lateral fold. Be- 

 tween these two folds on the back there may be no ridges at all or five or six 

 smaller secondary ridges or folds colored like the body and not as the dorso- 

 lateral folds and more or less broken in appearance. These intermediate folds 

 are more prominent in the young specimens. The muzzle is more acuminate 

 than in R. pipiens. A prominent fold below the eye to below the tympanum 

 in breeding males or to shoulder in others. Nostril about equidistant from the 

 end of the snout and eye. First finger longer than the second and about equal 

 to the fourth. Third finger larger than the rest. A tarsal fold more or less 

 present; fourth toe of R. sphenocephala longer than in R. pipiens, sometimes 

 longer by one or two phalanges in specimens of the same size. Three phalanges 

 of the 4th toe free. Inner metatarsal tubercle present. Tongue prominently 

 notched behind; vomerine teeth between inner choanae and in transverse 

 series. These characters not verified with 192 1 and 1922 material. 



MEASUREMENTS 



(Recent Material) 

 Head to angle of mouth .95 (28 mm.)-.96 (44 mm.)-i.o2 (56 mm.)-i.i3 

 (68 mm.)-i.i (82 mm.) in width of head; head to rear of tympanum .8-.83- 



