36 Prof. W. Thomson on the [Nov. 18, 



there a commensal Palythoa connected with this sponge ; the coil was 

 always perfectly clean. The spicules of the network and of the sarcode 

 closely resemble those of the Japanese species, but they all present 

 marked specific differences in detail of form. 



July 3. — We sounded in 2530 fathoms, with a bottom of reddish-brown 

 ooze (" red clay "), and took temperature-soundings ; we afterwards veered 

 the dredging-line to 1500 fathoms with tow-nets, and got many speci- 

 mens of the usual deep-water Protozoa. 



July 5. — We sent down the trawl and afterwards sounded in 2900 

 fathoms, and took serial temperatures. In the trawl, along with many other 

 deep-sea forms, there was one fine specimen of the large solitary hydroid 

 already referred to (Station 237). 



On the 7th we sounded in 3000 fathoms, with the usual bottom of red 

 clay ; on the 9th in 3050 fathoms, and on the 10th in 2950 fathoms. The 

 results of the dredgings for the last few stations had been so uniform, and 

 the operation was rendered so critical by the heavy swell from the westward, 

 that we did not consider it necessary to repeat it on every occasion. 



On the 12th of July the trawl was lowered at a depth of 2740 fathoms. 

 The net contained very few animals, and was greatly torn and frayed ; 

 but in a kind of pocket formed by an accidental folding of the net there 

 were about a cwt. of black mammillated concretions, which, when they 

 were poured out on the deck, had very much the appearance of potatoes. 

 The external surface of the concretion was slightly rough, and a number 

 of small anim al forms, particularly a minute rhizopod in a membranous 

 tube, nestled in the crevices. The nature of these concretions will be 

 discussed hereafter. 



On the 14th of July we reached the point lat. 38° 9' N., long. 156° 

 25' W., whence we turned southwards towards the Sandwich Islands. 

 For the last few stations the temperature of the water had been gradually 

 sinking, and the influence of the Japan current dying out ; the isotherm 

 of 10° C. was now only 100 fathoms below the surface. The depth at 

 this point was 3115 fathoms ; we put over the small dredge, as the nature 

 of the bottom had latterly been so destructive to the trawl, and brought 

 up manganese nodules, with a few small sponges and Bryozoa. 



On the 17th of July we sounded in 3025 fathoms, the bottom still 

 " red clay," and on the 19th in 2850 fathoms. A serial sounding taken 

 at the latter station to 1500 fathoms showed a considerable rise in the 

 temperatures near the surface, the isotherm of 10° C. having again sunk 

 to a depth of 200 fathoms, and that of 15° C. corresponding with the 100- 

 fathom line. On the 21st the bottom was " red clay " at a depth of 2950 

 fathoms ; the small dredge was lowered and brought up a large quantity 

 of the ooze, very smooth and tenacious, but containing scarcely a trace of 

 living things. The serial temperature-soundings indicated a still further 

 rise in the temperature of the upper layers, due doubtless to progress 

 southwards. 



