473 
Lake containing 100 specimens, ages 3 months and upwards, taken in 
late July, 1913. Out of 32 specimens over 32 months old, which were 
capable of 87 to 101% increase in body weight in the next 12 months, 
30 carried advanced embryos (midsummer brood) totaling 460. 
Figuring the average increase in body weight of young and adult 
age-groups in the next 12 months at 82.2%, the total body weight of the 
entire collection (without embryos), which was 72.286 grams at date 
of collection, would be approximately 131.7 grams one year later. Twelve 
months’ growth in the 460 embryos, assuming that all lived, might be 
expected to amount in the average individual to at least 4/5 of the aver- 
age body-weight of 12 to 15-month specimens (see table), or 233.6 mg. 
each, making the total weight-increment in the 460 embryos in 12 months 
107.4 grams. Adding the increase in the embryos and that in the young 
and adults to the original total body-weight of the collection (72.3 grams) 
we have, 12 months after date of collection, without making any allow- 
ance for increase from a spring brood, a hypothetical total weight of 
239.1 grams, or 3.3 times the weight with which we started. 
POSSIBILITIES OF GROWTH OF VIVIPARA CONTECTOIDES 
(BASED ON COLLECTION FROM SEEBS LAKE, JULY 25, 1913) 
| Av. rate increase in 
é | a Advanced embryos 
Age groups (estimated) body-weight next * 
12eonths (of midsummer brood) 
32 specimens over 27 months 87—101% ioe 460 (in 30 specimens) 
6 specimens, 24—27 mos. 91% | 
| 
22 specimens, 12—15 mos. 63% 
40 specimens, 3—4 mos. 82% | 
Total, 100 specimens 82.2% | 460 
Gross weight of collection, 94.0 grams. 
Body weight (corrected for loss in alcohol)................-++-- 72.3 grams 
Increase in body-weight next 12 months, at 82.2%.........4.... 59.4 it 
Increase in weight of embryos, next 12 months, at 233.6mg.* each 107.4 a 
NOEAT crete nisin sie =csiaiersietateve 239.1 grams 
=3.3 X original weight. 
* *Equals 44 of weight of 12—15-mo. specimens (preceding table). 
