104 THE AMERICAN NATURALIST. [VoL. XXXIV. 
weight, and the percentage dry weight. 
partial vacuum over sulphuric acid. 
They were dried in a 
TABLE V.— RANA SILVATICA. 
NuMBER OF| LENGTH Arce. An SPECIFIC - 
Dame TADPOLES ( ) sicui put in GRAVITY 
: : Weicut. | WeicHT | WEIGHT. ; 
April 13 5 21 .00328 001 36 41.4 LEII + 
April 13 5 4 .00 00132 38.37 LII — 
April 21 5 6 .00402 00142 34.8 1.055 
April 1 es IO 7 .00448 00126 28.1 1.055-1.037 
April 1 S IO 8-9 00540 00105 19.4 1.037-1.022 
April 21 5 9 00592 OO1IO 18.58 — 
April 21 IO IO-II 00794 OOIIO 13.9 | r.022-1.018 
April 22 5 13-14 02730 00144 B28 I.OIO 
April 26 5 16-17 04100 00208 5 — : 
April 28 5 16 05 2 4.5 1.009-1.0065 
May 1 5 20 .067 50 00356 &2. | 2007 
TABLE VI. — BUFO LENTIGINOSUS. 
NuMBEROF| LENGTH. ce en Tm SPECIFIC 
DATE FRESH Dry Dry 
TADPOLES. ( GRAVITY. 
EIGHT. | WEIGHT. | WEIGHT. 
May 1 IO 3-4 OOIIS .0005 44-3 1.037 
May 1 IO 4-5 00217 .0007 32.2 1.037 
May 2 IO 6 00339 -00065 19.1 1.025 
May 3 10 7 00354 00062 17.5 22 
May 1o 10 8-10 .00867 .00077 8.8 1.018-1.016 
May Io IO IO 01477 .00122 8.2 1.016 
May 10 IO 12. 02496 00196 7.8 1.018—1.016 
May 11 10 3-15 | .04455 | .00327 73 
These tables show : 
1. That the animals, while continually increasing in total 
weight, really decrease in dry weight up to the age (about 
IO mm. long in the frogs) where they take in food from 
without. 
