Royal Society. 67 



coma and A. clavata, a Trochus umbilicatus, and a Littorina lit- 

 torea were at different times added. 



Six weeks have now elapsed since the introduction of the ani- 

 mals. I have just carefully searched over the jar, as well as 

 I could do it without disturbing the contents. I find every 

 one of the species and specimens mentioned above, all in high 

 health ; with the exception of some of the Polyzoa, viz. Crisia 

 aculeata, Cellepora pumicosa, Cellularia ciliata, and Pedicellina 

 Belgica. These I cannot find, and I therefore conclude that 

 they have died out ; though if I chose to disturb the stones and 

 weeds, I might possibly detect them. These trifling defalcations 

 do in no wise interfere with the conclusion, that the experiment 

 of manufacturing sea-water for the Aquarium has been perfectly 

 successful. 



P. H. Gosse. 



58 Huntingdon Street, Barnsbury Park, 

 June 9, 1854. 



PROCEEDINGS OF LEARNED SOCIETIES. 



ROYAL SOCIETY. 



March 23, 1854.— Colonel Sabine, R.A., Treas. and V.P., 

 in the Chair. 



" Note on an indication of depth of Primaeval Seas, afforded by the 

 remains of colour in Fossil Testacea." By Edward Forbes, F.R.S., 

 Pres. G.S. &c. 



When engaged in the investigation of the bathymetrical distribu- 

 tion of existing mollusks, the author found that not only did the 

 colour of their shells cease 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 colour, and even the few that did so, were questionable 

 inhabitants of those depths. Between 35 and 55 fathoms, the pro- 

 portion of marked to plain shells was rather less than one in three, 

 and between the sea-margin and 2 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 colourless. 

 Between 60 and 80 fathoms, striping and banding are rarely 

 presented by our shells, especially in the northern provinces ; 

 and from 50 fathoms shallow-wards, colours and patterns are well 

 marked. 



The relation of these arrangements of colour to the degrees of 

 light penetrating the different zones of depth, is a subject well worthy 

 of minute inquiry, and has not yet been investigated by natural phi- 

 losophers. 



5* 



