84 The Bullfrog, Rana catesbeiana Shaw. 



It is not a distinct marbling, as in the green-frog. Tail considerably 

 lighter than the back and quite regularly covered with small black 

 spots (almost entirely lacking on the lower crest), some of which are 

 dumb-bell-shaped. The fine yellow dots are assembled in small groups. 

 Mouth-parts (Plate viii, Fig. 1) : Edge of upper lip about equal to 

 length of the horny beak and fringed with a continuous row of teeth. 

 In either corner, beneath this fringe, is a short row of teeth about one- 

 fourth of length of upper fringe. On the lower lip are three rows of 

 teeth, the first (the longest) often discontinuous; the second is almost as 

 long as the first; the third is much shorter. The dark-pigmented 

 papillae do not extend along the edge of the upper lip beyond the verti- 

 cal through the lateral tips of the horny beaks. Along the sides of 

 the lower labium are two series of papillae, the inner row of which usu- 

 ally terminates at the end of the lowest row of teeth. The middle 

 portion of the lower labium's margin, then, is with a single row of 

 papillae. Hinckley (1882) gives a third small row of teeth in the lower 

 corner of each upper lip; in 50 or more first-season, second-season, 

 and mature tadpoles, this occurred but once as she figures it. In two 

 other cases such a row was present, but it was at right or obtuse angles 

 to the first or second rows and might have been a part of one or both of 

 them. Sometimes the upper fringe is entirely absent, present on one 

 side, or the teeth of it may occasionally leave the mouth and be carried 

 back over the forehead. The second row may be missing or present 

 on only one side. In the lower labial teeth great variations obtain. 

 Sometimes all three rows may be discontinuous in the middle ; occasion- 

 ally the second or third row may be missing, seldom the first. Rarely, 

 when the outline, shape, and character of the papillae and margin of the 

 lips are uninjured and normal, the labial teeth of the lower labium may 

 be in considerable disorder with no suggestion of the three-rowed con- 

 dition. In some cases 18 or 19 short, abrupt rows extending in all 

 directions have been recorded. 



THE TADPOLE OF THE SECOND SEASON. 



The one year old tadpole (Plate ix. Fig. Ic) is generally like the mature 

 tadpole. Seldom, however, do they show the hind legs developing. 

 Instead of the venter being almost one continuous sheet of straw or 

 maize yellow, it is, except for the belly, mottled or marbled with straw 

 or maize yellow and the dark olive-green of the sides and back. 



THE TADPOLE OF THE FIRST SEASON. 



At the age of three to five months (Plate ix, Fig. 1b) the back of the 

 tadpole is greenish brown, the background covered with very fine dark 

 specks which show best on the sides, where the finely sprinkled yellow or 

 gilt spots are fewer. These are gathered in closely set groups very near to 

 each other. Some of the groups in their formation remind one of snow 

 crystals. All over the back are the characteristic black circular spots, 



