86 
THE VOYAGE OF H.M.S. CHALLENGER. 
Michael Saks. 
Mac An drew s 
Observations. 
Woodward. 
>rii ring up eight species of Mollusca, including Pleurotoma maritima, a species be- 
lonuing to the cor.dline crag, which was supposed to be extinct. They were examined 
b\ Gw vn Jell revs, who found them to be identical with species dredged subsequently at 
considerable depths in the North Atlantic by the “ Porcupine.” Spratt was of opinion that 
life existed at much greater depths, though the general character of the AEgean Sea tended 
t l.mit the depth to 300 fathoms. 1 In his survey of the Mediterranean between Malta 
ind Crete, he afterwards procured fragments of shells, &c., from a depth of 1620 fathoms. 2 
Like Loven, Spratt proved that temperature influenced the distribution of marine 
organisms. He found in the six upper zones of Forbes summer temperatures of 30°, 
23°, 20°, 16°G, and 13°'3 C.; thus it might be said that different depths corresponded to 
different latitudes. 
Before 1850 the attention of the Norwegian naturalist, Michael Sars, had been 
dire ted to the bathymetrical distribution of life on his native coasts, and he published 
ih that vear a list of nineteen species which lived at depths greater than 300 fathoms. 
His son, G. O. Sars, afterwards assisted him in the work of deep-water dredging, and the 
result was, in 1864, a list of ninety-two species, which lived between the depths of 200 
and 300 fathoms. A few years later these untiring investigators found abundance of 
life at the bottom under 450 fathoms of water. 
In his Report to the British Association on the marine testaceous Mollusca of the 
north-ea-t Atlantic and neighbouring seas, 8 MacAndrew refers to the distribution of 
Mollusca along the coasts of Europe and Africa from the North Cape to the Canary 
I d nd.s, showing of what the fauna consists over this extent of ground, how it becomes 
modified towards the south, and pointing out the species found also on the coasts of North 
America. He gives a table of 750 species obtained in his dredgings, which extended over 
13 degrees of latitude, showing the horizontal and vertical distribution of each, the locality 
of t. ir greatest development, the nature of the bottom, &c. A second table shows the 
g.-..graphii\d distribution of these species, among which are recorded 275 Acephalse, 14 
Pteropod i, and 460 Gasteropoda. He asserts that the Acephalae have a greater batliy- 
raetrieal and horizontal extension than the Gasteropoda, several species being found at 
ill depths down to 100 fathoms and even more. As a general rule, the deeper species 
ip ;u. Her, th ir colours less bright, and the test less robust than the shallower species. 
M;.' A ud row s work proves that the exact distribution of marine Mollusca into provinces 
or faumc is far from being so precise as was at one time imagined. 
In his well-known book, Manual of the Mollusca (1851-56), S. P. Woodward gives 
mu - li inN renting information on the distribution of the Mollusca, valuable alike to the 
paleontologist and zoologist. 
The influence of the work carried out by the United States Coast Survey on oceano- 
A -« IU-pori for 1848, Tran*, of Sections, p. 81. * Spratt, Travels and Researches in Crete, voL ii. p. 329. 
’ hrii At*. Report for 1858, pp. 101-168. 
