204 Influence of Temperature on the Depth of Marine Species. 
sparkling light show itself except in the muscles and at the mo- 
of contraction. here may, undoubtedly, exist on this 
point, reasonable uncertainty with regard to those Annelids 
whose foot muscles are lodged in the abdomen; but this can- 
not be true with respect to the Ophiura, and nothing is easiet 
than to prove this even to the unaided vision, as in the latter 
the phosphorescence appears along the arm and only during 
movement. Moreover, the details which will be given beyond 
of the phosphorescence of the Noctiluce will show plainly, 1 
believe, that these animals have no special organ for producing 
the light. 
Finally, the Photocharis observed by Ehrenberg secreted & 
liquid which left luminous traces on the objects which came 1 
contact with it. This peculiarity I have also met with in one 
of my Annelids; but generally in the latter and especially also 
the Ophiura, the light was owing entirely to the scintillations 
and di with them. It is however easy to believe that 
the modes of phosphorescence which we have admitted may ¢ 
exist in the same animal. 
(To be continued.) 
pinkie 
Arr. XXIIL—On the question whether Temperature determines 
the Distribution of Marine Species of Animals in Depth; hy 
A. 
James D. Dan 
Ir is a question of much interest, how far temperature ivi 
ces the range of zoological species in depth. From a survey © 
the facts relating to coral-zoophytes, the author arrived a the 
conclusion that this cause is of but secondary importan™ 
After determining the limiting temperature bounding the com” 
reef seas, and ascertaining the distribution of reefs, it was wad 
to compare this temperature with that of the greatest depths @ 
which the proper reef corals occur. This depth is but ! 3 
Now the limiting temperature, 68°, is reached under the eq” th 
at a depth of 500 feet, and under the parallel of 10° at dep 
of at least 300 feet. There must therefore be some other © of 
besides temperature; and this may be amount of pressurts 
light, or of atmospheric air dissolved in the waters. the 
Prof. Forbes has remarked that the deep sea species ne’ 
HEgean have a boreal character ;+ and Lieut. Spratt has 
tained the temperatures at different depths,} and shown rer 
deep sea species are those which have the widest range of or 
bution, most of them occurring north about the British short — 
eh ee Report on Zoophytes, 1846, p. 103; and on Geology, P- a; ae 
+ Report on the Aigean Tn: Brit. Assoc. 1843, 130. 
t Rep. Brit. pe, sf thera “r a sth 
