Rana heckscheri 391 



bars of black where the myocommas are. These overshadow the intervening 

 body color. Whole rim of tail or edge of crests black, least just in front of 

 the vent. 



Iris rim above and below orange cinnamon, tawny vinaceous, tawny or 

 orange rufous or better vinaceous rufous. Iris rim in front and behind 

 pupil black. 



General appearance. Tadpole quite large (97 mm.), usually black of body, 

 and the most striking of all our (U. S.) Rana tadpoles. Belly pigmented so 

 intestine does not show through in preserved specimens. Tail elongate, tip 

 acuminate; dorsal crest not as wide as musculature width; not much different 

 from lower crest and not extending on body beyond the vertical through the 

 buds of the hind limbs. Spiracle sinistral, just visible from dorsal aspect, 

 divided backward and somewhat obhquely upwards. Spiracle usually with a 

 distinct semicircular impression on body and opening. Opening, leaving ex- 

 posed an elliptical or hemispherical patch on body. Spiracle clearly below 

 lateral axis (musculature axis). Eye on or just above lateral axis but in dorsal 

 aspect nearer lateral outline than mid-dorsal axis. Anus dextral opening at 

 edge of ventral crest. 



Muciferous crypts distinct, white: a short dorsal row of a few pores on 

 either side of middle line of the back from the dorsal crest forward; from above 

 the middle Hne of insertion of tail musculature on body to a short distance 

 behind eye a prominent dorsolateral row; apparently resumed behind eye 

 after an interval and continued as supraorbital and infraorbital hues to above 

 and below the nostril; another lateral row from above insertion of hind legs to 

 gill region where a ventral commissure goes across to the row of the other side. 

 A third of the distance across the ventral branchial region a branch from the 

 commissure goes outwards and forwards along the jaw region almost to 

 the mouth. 



Mouth parts. Teeth 2/3 or 3/3. Edge of upper labium greater than 

 length of upper horny beak and fringed by a continuous row of teeth. Some- 

 times this fringe is broken up as in figure. In either corner, beneath this fringe 

 is a short row of teeth about one-fourth to one-third of the length of the upper 

 fringe. The outer end of this second row never reaches outward beyond the 

 first fringe. Median space between these second rows of teeth, one to one and 

 one-half times the length of either lateral series of the second row. In some 

 median-sized tadpoles the space may be greater and the second row much 

 shorter or rarely absent. The third upper row very short, frequently absent 

 in young and medium-aged tadpoles. From above the end of the first upper 

 labial row of teeth to beneath the end of the third lower labial row are two or 

 three irregular rows of papillae which are continued across lower labium's 

 edge as one serrate row. The third labial row longer than this single row of 

 papillae equal to length of horny beak but 1/4-1/5 shorter than first and 

 second rows which extend beyond the ends of the horny beaks. The first row 

 is continuous or broken in the middle. 



Measurements. Length of body (32.0-41.5 mm.) in tail (50-57.5 mm.) 

 1. 4-1. 85, average 1.625. Width of body (15.0^22.5 mm.) in its own length 



