171 
Du rig en States that the size of the larvæ is lying between 48 
and 50 mm, in rare cases between 70 and 80 mm. In 1908 
Wesenberg-Lund observed in a Danish pond a great number 
of two-legged esculenta larvæ varying in size from 30 to 100 mm, 
a few of them measuring even 115 mm. In the course of the 
autumn part of them completed their metamorphoses, while at this 
juncture the rest remained quite larval. The young frogs, after the 
metamorphosis, measured 25—40 mm in length. By roentgenography 
it was established that the ossification was less advanced in the 
giant larvæ than was the case of the normal ones at the same 
stage of development. The thyroid was examined both in some of 
the normally sized larvæ and in three giant larvæ at different 
stages (fig. D. a.—c.), measuring respectively 100, 93 and 64 mm. 
In all of the giant larvæ a strumiform enlargement of the thyroid 
was found, the organ being built of numerous larger and smaller 
follicles with interstitial cell herds and other indications of proli- 
feration. In two of the larvæ (a. and b.) only traces of colloid matter 
were demonstrable, whereas the follicles of the third nearly meta- 
morphosed specimen (c.) showed vacuolated colloid matter (fig. 23). 
The thyroids of the normally sized individuals from the same pond 
showed nothing in particular. The abnormal condition of the thy¬ 
roid in the three giant larvæ, as compared to that of normal larvæ 
at the very same stage of development, is most easily perceptible 
by comparing fig. 22 to fig. 25 (originating in tadpole of fig. C. c.) 
and fig. 23 to fig. 26. — 
The causal relationship of this gigantism was not established 
with any degree of certainty. In the larva of fig. D. c. the hypo- 
physis was found to be enlarged ( 0,88 X 1,52 mm), the same 
being the case in another somewhat smaller larvæ (1 ,i6 X 1,26 
mm); in a good-sized normal larva (80 mm) the hypophysis meas¬ 
ured 0,63 X 0,97 mm. The genital giands of the giant larvæ did 
not seem to be either copiously or prematurely developed to any 
degree worth mentioning. 
12 - 2 - 1921 . 
