498 BENNET M. ALLEN 
members of the former group that have a thyreoid gland volume 
approaching that of any member of group II. The same is true 
in comparing group II with group III (with the single exception 
of II h). These statements do not hold true, however, in com- 
paring groups IV, V, and VI. In these there are a number of 
cases in which members of a younger stage will show a greater 
volume of the thyreoid glands than do certain individuals in the 
higher groups. In fact, the average volume of the thyreoid 
glands in group V is less than that of group IV. This point. 
will be discussed later. Even among the metamorphosed toads, 
VI h, for instance, shows a thyreoid gland volume less than the 
TABLE 2 
Dimensions of thyreoid glands and body measurements of Bufo lentiginosus larvae 
TAIL BODY LEG > THYREOID | THYREOID: 
I BODY G ID 
STAGE Eee PROPOR- Paes PROPOR- eo PROPOR- pi girs 3 PROPOR- 
TION TION > TION : V VOLUME TION 
mm. mm. mm, cmm. 
I 11.09 | 0.742 | 9.69 | 0.770 | 1.21 | 0.104 | 0.00139) 0.0518 | 0.0635 
Th 13.88 | 0.954 | 11.65 | 0.926 | 3.67 | 0.314 | 0.01270) 0.5026 | 0.616 
Ill 14.95 | 1.000 | 12.07 | 0.959 | 7.76 | 0.664 | 0.02612) 0.6390 | 0.771 
IV 13.63 | 0.912 | 11.13 | 0.885 | 9.17 | 0.785 | 0.03161} 0.6811 | 0.834 
Vv 2.91 | 0.195 | 11.58 | 0.920 | 10.49 | 0.898 | 0.03077| 0.6753 | 0.828 
VI 0.00 | 0.000 | 12.58 | 1.000 | 11.69 | 1.000 | 0.05427} 0.8158 | 1.000 
averages of groups IV and V, while the thyreoid volume of VI d 
is surpassed by the thyreoid volume of several individuals in 
each of the two preceding classes. It may be pointed out that 
this is partially to be explained by the fact that these three 
stages are really passed through in a relatively short period of 
time. Figure 6 shows the thyreoid glands of VI f. 
Table 2 shows the average dimensions of the body and of the 
thyreoid gland in each of these groups. The actual dimensions. 
are given, and in the following column is shown, in each case, 
the proportional size of the feature as compared with the size at. 
the stage when it shows its maximum development. 
Text figure A gives a graphic representation of these features 
as seen in table 2. In this case the growth of the hind limbs was. 
taken as a standard for determining the relative stage of devel- 
