392 Mr. Gwyn Jeffreys on Dredging among the Hebrides. 
doubt can be entertained. I have myself seen a number of 
Antedon (or Comatula) celticus clinging to the rope several feet 
from the dredge when it was taken up from about 60 fathoms. 
These starfishes must have crawled up the rope while the dredge 
was in motion or being hauled in, because no part of the rope 
had lain on the ground. Dr. Carpenter tells me that Antedon 
rosaceus has the same habit of crawling up and clasping a rope 
in shallow water. 
The greatest dently marked on the Admiralty charts in any 
part of the Hebridean sea-bed which I examined is 182 fathoms. 
Here I got several kinds of living Foraminifera. Nineteen 
years ago I dredged near the same ground, in 116 fathoms, a fine 
cluster of one of the compound Tunicata, Diazona Hebridica, 
of a greenish-pink colour. I do not mention this as a great or 
even considerable depth. Sars* and Koren+ have done much 
more on the coasts of Norway; their dredging-explorations 
extended to 800 fathoms. In the paper from which I have 
extracted the above remarks as to the distribution of animal life 
in the depths of the sea, Professor Sars has enumerated no less 
than 52 species and distinct varieties of animals found by him 
at the depth of 300 fathoms. They may be thus classified :— 
Porifera (Sponges) 2; Rhizopoda (Foraminifera) 19; Polypi 
(Actinozoa) 7; Mollusca (Polyzoa 8, Tunicata 1, Mollusca proper 
10) 19; and Vermes (Annelida) 5. He has also specified several 
Echinoderms, Cirripeds, and Crustacea, as inhabiting somewhat 
less depths, viz. from 200 to 250 fathoms. The observations 
of the learned Norwegian zoologist confirm those of Sir James 
Ross and Dr. Wallich, namely :— 
lst. That the temperature of the sea is uniform (39°°5 Fahr.) 
over the whole globe, below a certain line which forms an isother- 
mal curve, with but slight oscillations caused by changes of the 
atmosphere. This curve has its greatest depth at the Equator, 
but reaches the surface of the ocean in lat. 56° 62', and dips 
again as it approaches the pole from this point. 
”Ond. Although the pressure of the water is enormous at great 
depths, and in 300 fathoms is equal to about 56 atmospheres 
or 840 lbs. on the square inch{, yet the most brittle and delicate 
animals (such as Polyzoa and Polyps) inhabiting such depths do 
not appear to suffer the slightest mjury. Their structure is 
porous and permeable by liquids, or accessible to an endosmotic 
influence by which the pressure is easily resisted. 
* Reise i Lofoten og Finmarken, 1849. 
+ Nyt Mag. Naturw. 1856. 
{ The Norse skaalpund is 10 per cent. more than the English lb. avoir- 
dupois. Sixteen Norwegian square inches are equal to seventeen English 
square inches. 
