83 
1907-8.] The Body-Temperature of Fishes, etc. 
The figures given in the table on p. 81 are, for the most part, con- 
siderably higher than any obtained by me. In the smaller specimens 
examined (haddock, flounder, smelt, and immature coal-fisli), there was 
practically no difference between the temperature of the fish and that of the 
water. Of 25 flounders, ranging in weight from \ to .2 lbs., 1 showed a 
temperature difference of 0°*2 C., 5 of 0 o, l C., and in the remaining 19 
the temperature of the water and of the fish was the same. Even in the 
large cod-fish and ling, which were examined under the most favourable 
conditions for the development of heat, viz. immediately following violent 
muscular exercise, the excess of temperature never reached 1°*0 C., and 
seldom exceeded 0 o, 5 C. 
Similarly with regard to the crustaceans and echinoderms which have 
come under my observation : the records obtained are far lower than any 
of the figures given by other observers. Valentin has arranged the marine 
invertebrates in the order of their heat-producing capacity, as measured 
by the temperature difference between the animal and the medium, and 
has found that this series runs parallel with the zoological series. Although 
it is highly probable that this arrangement is more or less artificial, my 
results agree with it in so far that the mean for the echinoderms is below 
that for the crustaceans. From 53 echinoderms (45 sea-urchins and 8 
starfishes) the mean temperature difference was 0°025 C., while from 100 
crustaceans (59 shore-crabs, 40 edible crabs, and 1 lobster) it was 0 o, 069 C. 
After Valentin. 
Polypes .... 
Medusae .... 
Echinoderms 
Molluscs . . . . 
Cephalopods 
Crustaceans 
. 0*21 C. 
. 0-27 
. 0-40 
. 0*46 
. 0-57 
. 0-60 
It would be quite erroneous and misleading to assign to any of the 
species which I have examined a definite excess of temperature over that of 
the medium in which they live. The body-temperature is inconstant in a 
twofold sense : it varies with the temperature of the medium, and the 
difference between it and that of the medium also varies probably from 
time to time. The attempt at regulation is of the very feeblest, and in 
most of the species it can hardly be said to exist at all. 
SUMMAKY. 
The body-temperature of the following fishes, crustaceans, and echino- 
derms has been examined and compared with the temperature of the 
water in which they live : — Cod-fish ( Gadus morrhua), ling (Molva vulgaris ), 
