ART 11 NORTH AMERICAN TADPOLES— WRIGHT 19 



crest. Muciferous crypts indistinct in preserved specimens. Some- 

 times the tadpoles do not grow big before transformation. 



Mouth parts. — Teeth f , f , rarely f . Whole labium (upper and 

 lower) with a continuous row of papillae except on the upper labium 

 where a short median interval is toothed. This median row, unlike 

 the tadpole of S. liolhrookii is not equal to the first lower labial row 

 of teeth, but is contained 1.5-2.9 times or more in this row. There 

 is no inner row of papillae. The next row of teeth below the toothed 

 interval is interrupted, the inner ends of this row seldom extending 

 much below the ends of the toothed intervals unlike S. holhrooJcii, i. e., 

 the median interval in the second row about equals the first row, or 

 is slightly less. The third row has a wide median interval two to 

 three times the first papillary toothed row. Either half of the third 

 row is 0.4-0.3 times of the mandibular beak and about equal to the 

 second lower labial row. Either one part of the fourth row is equal 

 or sometimes twice the median interval of the second upper row. 

 The fifth may be present on each side or absent on one side and 

 present on the other, but usuall}^ is absent on each side. 



On the lower labium are four series, the first three not continuous 

 in the middle, the last continuous. The median interval of the first 

 row is considerably less than the horny beaks and greater than the 

 fourth series of teeth. The interval of the second series is usually 

 about or less than that of the third upper row. The third lower 

 series has a very sHght median interval, less than the first dorsal 

 row or the median interval of the second upper row. The fourth 

 and last row is about equal to either lateral half of the upper second 

 row or one half the length of the horny beak. Last rov/ of teeth 1 .75- 

 2.0 in next to last lower row of teeth. 



Measurements. — Length of body (17-28.0 mm.) in tail (23-37.0 mm.) 

 1.32-1.66, average 1.49. Width (12.6-18.0 mm.) of body in its o\^ 

 length 1.55-1.9, average 1.66. Depth (12-15.5 mm.) of body 1.05- 

 1.15 in body wddth, average 1.09. Depth of body 1.6-2.0 in body 

 length, average 1.79. Depth (10.6-15.5 mm.) of tail in length of 

 tail 2.05-2.9, average 2.44. Muscular part (4.4-6.5 mm.) 2.25-2.66 

 in depth of tail, average 2.43. Spiracle 1.25-1.35 nearer base of hind 

 legs or vent region (10-13 mm.) than the tip of the snout (13.0- 

 17.5 mm.), average 1.30. Spiracle 1.25-1.6 nearer eye (7.8-10.5 mm.) 

 than base of hind legs or vent, average 1 .37. Eye 1.1-1.3 nearer to tip 

 of snout (6.0-9.0 mm.) than to spiracle (7.8-10.5 mm.) 1.1-1.3, average 

 1.2. Nostril 1.4-2.5 nearer eye (2.0-2.0 mm.) than snout (4.0-6.0 

 mm.), average 2.05. Mouth (4.8-5.5 mm.) usually 1.8-2.5 larger 

 than internasal space (2.0-3.0 mm.), average 2.25. Mouth contained 

 1-1.16 (average 1.08) in interorbital distance (5.0-5.6 mm.). Inter- 

 nasal space contained in interorbital space 2.5-2.75, average 2.6. 



