302 ANNUAL OF SCIENTIFIC DISCOVERY. 



existing rnollusks, the author found that not only the color of their shells 

 ceases to be strongly marked at considerable depths, but also that well- 

 defined patterns were, with very few and slight exceptions, presented only 

 by testacea inhabiting the littoral, circumlittoral and median zones. In the 

 Mediterranean, only one in eighteen of the shells taken from below 100 

 fathoms exhibited any markings of color, and even the few that did so 

 were questionable inhabitants of those depths. Between 35 and 55 

 fathoms, the proportion of marked to plain shells was rather less than one 

 in three, and between the margin and two fathoms the striped or mottled 

 species exceeded one- half of the total number. In our own seas^the author 

 observes that testacea taken from below 100 fathoms, even when they were 

 individuals of species vividly striped or banded in shallower zones, are 

 quite white or colorless. Between 60 and 80 fathoms, striping and band- 

 ing are rarely presented by our shells, especially in the northern provinces ; 

 and from 50 fathoms, shallow bands, colors and patterns are well marked. 

 The relation of these arrangements of color to the degrees of light penetrat- 

 ing the different zones of depth is a subject well worthy of minute inquiry, 

 and has not been fully investigated by natural philosophers. Proceedings 

 of the Royal Society. 



THE GULF STREAM. 



At the American Association, Prof. Bache read a paper on the distribu- 

 tion of temperature in and near the Gulf Stream, of the coast of the 

 United States. 



On the seaward line off Charleston, from the shore to sixty miles out, 

 the depth increases gradually till it acquires a depth of one hundred fath- 

 oms. But it soon deepens with great rapidity, as if on the side of a moun- 

 tain, until at about eighty miles out the ocean-bottom is more than six 

 hundred and fifty fathoms from, the surface. This continues forward less 

 than ten miles, when the depth as suddenly decreases to not more than 

 three hundred and fifty fathoms, which so goes on only a few miles, when 

 it again deepens to about five hundred fathoms, with subsequent fluctua- 

 tions. There is, therefore, a submerged mountain -peak or ridge between 

 these points of a truly remarkable character. The differences in the tem- 

 perature vary almost precisely according to the change of contour of the 

 bottom, showing that the temperature at great depths is much modified by 

 the propinquity of the ocean's bed. It appears that the Gulf Stream, 

 while certainly not superficial, does not run to the bottom ; for off Cape 

 Florida, at twelve hundred fathoms, the water in summer is of a tempera- 

 ture of 38 Fahrenheit a degree below the average winter temperature 

 much farther north. 



Lieut. Maury followed Prof. Bache. He showed that the stream varies 

 its course according to the season, having a more southerly sweep in win- 

 ter. The stream is more rapid of. Cape Hatteras than Cape Canaveral, 

 and never deposits the seaweed, with which it is so plentifully beset, on 



