1870.] 



Deep-sea Researches. 



173 



Mario foss.) ; Solarium pseudoperspectivum 3 Brocchi (Sic. foss.) ; Mitra 

 zonata, Marryat (Sic. foss.) ; Mytilus incurvatus, Ph. (Sic. foss.) ; Sportella 

 Cailleti, Conti (Monte Mario foss.). 



50. - During the night we again steamed out into Deep water, and on the 

 morning of Aug. 26th found at Station 45 a depth of 1415 fathoms, with 

 a bottom-temperature of 54°' 7. The Density of the Bottom-water was 

 almost exactly the same as that of the two previous deep-water samples. 

 Our dredging was here more successful, the following species of Mollusca 

 being obtained: — Nucula, sp. n. (quadrata) ; N.pumila, Asbjornsen (north- 

 ern) ; Leda, sp. n. (Portuguese also) ; Pecchiolia granulata, Seg. (Sic. 

 foss.); Hela tenella, Jeffr. (northern, and Sic. foss.); Trochus gemmu- 

 latus, Ph. (Sic. foss.) ; Rissoa subsoluta, Aradas (Sic. foss.) ; Natiea affinis, 

 Gmelin (northern, and Sic. foss.) ; Trophon multilamellosus, Ph. (Sic. 

 foss.) ; Nassa prismatica, Br. (Sic. foss.) ; Columbella halioeeti, Jeffr. 

 (northern, and Sic. foss.), % — Buccinum acuticostatum, Ph. ; Pleurotoma 

 carinata, Cristofori and Jan (northern, and Sic. foss.) ; P. torquata, Ph. 

 (Sic. foss.) ; P. decussata, Ph. (Sic. foss.) ; Planorbis glaber, Jeffr. (fresh- 

 water !) ; Spinalis physo'ides s Forbes, = £. recurvirostra, A. Costa. 



5 1 . Directing our course again towards the Algerine Coast, we kept nearly 

 parallel to it during the greater part of the next day, occasionally sweeping 

 the bottom with the " tangles," which gave us abundance of Polyzoa, 

 Echinoderms, &c. of well known types, without any specimens of novel or 

 peculiar interest, except (at Station 50, in 7-51 fathoms) a specimen of 

 Trochus biangulatus, Eichwald, fide Homes, = T. ditropis, S. Wood, a Mio- 

 cene and Coralline Crag shell. We reached Algiers on the afternoon of the 

 26th ; and as it was necessary to take in coal, we remained in harbour until 

 the 29th, when we resumed our easterly course, still keeping near the Coast. 

 The weather now began to be oppressively hot, the Surface-temperature of 

 the Sea rising to 76° or 78°, and that of the Air being often several degrees 

 higher. Wishing to see what would be the point at which the effect of 

 this extreme superheating would cease to manifest itself, we took a set 

 of Serial soundings at Station 53, with the following result, which we in- 

 cline to consider typical of the condition of the proper Surface-water of 

 the Mediterranean in the Summer season : — 



° Fahr. 



Surface 77 



5 fathoms 76 



10 „ 71 



20 „ 61-5 



30 „ 60 



40 „ 57*3 



50 „ 56-7 



100 ,, 55-5 



Thus the amount of heat lost in the first 20 fathoms is no less than 15°*5 ; 

 and as much as 9°'5 of this loss shows itself between 10 and 20 fathoms. 



