[Illustration: FIG. 16. Relative rate of growth in tadpoles of _Smilisca phaeota_ as correlated with developmental stages. Formulas for the limb bud refer to its length (L) in relation to basal diameter (D).] _Stage 25._--Operculum complete; gills absent; sinistral spiracle apparently functional; cloacal tail-piece, nasal capsules, and external nares present; gut partly formed; mouth bordered by single row of papillae, except medially; small papillae present in lateral fold of lips; two upper and three lower tooth-rows present, but not fully developed; beaks apparently fully developed; depth of dorsal and ventral fins less than depth of caudal musculature: tip of tail upturned; pigment on body most dense on dorsum and sides; faint, nearly pigmentless crescent-shaped mark on posterior edge of body; concentrations of pigment forming small spots on tail. _Stage 28._--Mouthparts complete; limb bud about half as long as thick; other structural features and coloration closely resemble those in stage 25. _Stage 30._--Limb bud approximately twice as long as thick; body as deep as wide; dorsal fin deepest just posterior to body; ventral fin deeper than caudal musculature; tail sharply upturned distally; anal tube dextral; brown pigment sparse on flanks. Table 11.--Growth and Development of Tadpoles of Smilisca phaeota. (Means Are Given in Parentheses After the Observed Ranges.) ==================================================================== Stage | N | Total length | Body length | Tail length -------------------------------------------------------------------- 15 | 10| -- | 1.9-2.1 (1.97) | -- 16 | 8| -- | 2.0-2.2 (2.07) | -- 18 | 4| -- | 2.2-2.6 (2.31) | -- 21 | 3| 7.9-8.6 (8.21) | 4.1-4.5 (4.31) | 3.8-4.1 (3.92) 25 | 10| 8.7-10.6 (9.69) | 4.5-4.8 (4.64) | 4.3-6.0 (5.05) 26 | 11| 12.3-16.1 (14.01) | 4.2-6.3 (5.60) | 6.7-9.8 (8.41) 27 | 10| 13.0-15.7 (14.28) | 4.9-6.2 (5.40) | 7.7-10.5 (8.88) 28 | 13| 13.9-20.9 (15.62) | 5.2-8.3 (5.75) | 8.5-12.6 (9.85) 29 | 8| 17.8-22.3 (19.79) | 6.3-8.4 (7.19) | 11.5-14.0 (12.60) 30 | 9| 20.3-24.8 (22.85) | 8.1-10.5 (9.32) | 10.5-15.5 (13.53) 31 | 5| 24.1-28.5 (26.61) | 9.4-11.2 (10.59) | 14.7-17.3 (16.02) 34 | 5| 24.8-29.4 (27.31) | 9.2-11.6 (10.73) | 15.6-18.5 (16.80) 36 | 3| 30.0-30.1 (30.07) |10.1-12.2 (11.15) | 18.9-20.0 (19.44) 37 | 4| 28.9-34.1 (31.75) |11.5-12.4 (11.88) | 17.4-22.5 (19.88) 38 | 1| 28.98 |12.88 | 16.10 39 | 2| 35.6-36.9 (36.25) |14.00 | 21.6-22.9 (22.25) 40 | 2| 32.3-39.8 (36.05) |14.00 | 18.3-21.8 (20.05) 43 | 2| 21.5-23.0 (22.25) |14.2-14.8 (14.45) | 6.8-8.8 (7.80) 44 | 4| -- |14.5-15.6 (15.08) | --