190 REPORT— 1866. 



cured living starfishes fi-om a depth of 1260 fathoms, under the circumstances 

 which he has described (viz. " convulsively embracing a portion of the 

 sounding-line, which had been paid out in excess of the akeady ascertained 

 depth, and rested for a sufficient period at the bottom to permit of their 

 attaching themselves to it"), no reasonable doubt can be entertained. I have 

 myself seen a number of Antedon (or Comatula) celtieus clinging to the rope 

 several feet fi-om the dredge when it was taken up from about 60 fathoms. 

 These starfishes must have crawled up the rope while the di'edge was in 

 motion or being hauled in, because no part of the rope had lain on the ground. 

 Dr. Carpenter teUs me that Antedon rosaceiis has the same habit of crawling 

 up and clasping a rope in shallow water. 



The greatest depth marked on the Admiralty charts in any part of the 

 Hebridean sea-bed which I examined is 132 fathoms. Here I got several 

 kinds of living Foraminifera. Xineteen years ago I di'edged near the same 

 ground, in 116 fathoms, a fine cluster of one of the compound Tunicata, 

 Diazona Hehrid'iea, of a greenish-pink colour. I do not mention this as a 

 great or even considerable depth. 8ars* and Korenf have done much more 

 on the coasts of Norway ; their dredging-explorations extended to 300 

 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 he thus classified : — Porifera 

 (Sponges) 2 ; llhizopoda (Foraminifera) 19 ; Polypi (Actinozoa) 7 ; MoUusca 

 (Polyzoa 8, Tunicata 1, Mollnsca proper 10) 19; and Yei-mes (Annehda) 5. 

 He has also specified several Euhinoderms, Cirripeds, and Crustacea as in- 

 habiting somewhat less depths, viz. from 200 to 2.50 fathoms. The obser- 

 vations of the learned Norwegian zoologist confirm those of Sir James Ross 

 and Dr. AYallich, namely : — 



1st. That the temperature of the sea is uniform (39°-5 Fahr.) over the 

 whole globe, below a certain line which forms an isothermal 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. 



2nd. 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 X, yet the most brittle and delicate animals (such as Polyzoa and Polyps) 

 inhabiting such depths do not appear to suffer the slightest injuiy. Their 

 structui'e is porous and permeable by liquids, or accessible to an endosmotic 

 influence by which the pressiu'e is easily resisted. 



3rd. The want of light has always been considered an obstacle to the exist- 

 ence of animal life at great depths — not so mucli because light is dii'ectly 

 essential to animal life, as on account of its indirectly contributing to its 

 maintenance. It is generally supposed that animals are dependent on vege- 

 table life. This latter (as is well known) cannot exist without light, under 

 the influence of which the absorption of carbonic acid and the evolution of 

 oxygen are eftected. Light, however, exerts no such influence on animal life. 

 Sea-weeds (the true Alga)) disappear in about 200 fathoms ; and the only 

 vegetable organisms which descend to a greater depth, say 400 fathoms, are 

 DiatomaceEe. It may be observed, with respect to the action of light in 

 producing colour in animals, that although intensity of light may produce 



* Eeise i Lofoten og Finmarken, 1849. t Nyt Mag. Naturw. 1856, 



X The Norse skaalpuud is 10 per cent, more tlian the English lb, avoirdupois. Sixteen 

 Norwegian square inches are equal to seventeen English square inches. 



