244 MR. E. 8. RUSSELL ON THE SHELL-GROWTH [ Mar. 2, 
3. Variation in Rate of Growth with Increase in Size. 
The rate of growth decreases with increase of size. This fact 
is shown by the data already given, but in order to gain a precise 
knowledge of the manner of the decrease it is necessary to dis- 
count the possible influence of time of year and temperature upon 
the rate of growth. This has been done by taking the figures 
given in Table I., for the period July 30th to September 2nd, and 
considering along with them some other additional data which 
have reference also to the month of August. These are, 
(1) observations on the growth of 10 limpets at the Cloch, 
Gouvock, from the end of July to the second week in September 
1906 (43 days), and (2) on a similar number at the same place 
from July 31st to September 7th, 1907 (38 days). <A few 
additional data referring to seven limpets at Kames, during July 
1906, are also incorporated. The detailed observations are given 
in the following Tables. 
TasxeE III. 
Growth during 43 days. The Cloch, Gourock, Aug. 1906. 
| | 
is | weft By 2 : Growth per cent. 
Group. Original size. = Final Size. | in 30 days. 
20°6 25°5 16°59 
20—25 mm. 21 27 19°93 
| 23-4. | 27 10°73 
(25 O77 7°53 
rm | ) 26 29°5 9°41 
25—30 mm. 5 265 38 3:95 
| (27 312 10°85 
40—45 mm. ; tae z ° a 
| 
45—50 mm. 46 | 46°5 ‘76 
TaBLe LV. 
Growth from July 31 to Sept. 7 (38 days). The Cloch, Gourock. 
| Growth per cent. | 
Group. Original Size. | Final Size. | in 30 days. | 
16-4 219 | 2648 | 
15—20 mm. 18 21 13°16 | 
19°8 | 23'5 14:75 | 
| | 
35—40 mm. 391 43°6 | 9-08 | 
Le f 42°5 43°5 1°85 | 
aR Se ae 43°5 45°7 3°99 
(46-2 AT 1:37 
eee | 46°5 ATS 1-69 
45—50 mm. < 46°8 Ar 1-01 
