50 Mr. C. W. Peach on Nature-Printing of Sea-weeds. 



margins ; the darker spot of the back very obscurely indicated. 

 There were only two, in a large series of specimens, in which these 

 marks were distinct, and in them they were paler than usual. 

 The base very pale yellowish, rather darker between the teeth 

 of the aperture. 



5. Cyprcea staphylcea. The larger number of the specimens 

 of this species are bright orange-yellow, polished, and without 

 any of the usual white tubercles. Some of them have an irre- 

 gular white blotch on each side. 



Some specimens have more or less distinct small white dots 

 on the back, in place of the tubercles ; one large specimen has 

 these spots very slightly raised, thus approaching the normal 

 state of the species. 



With these shells were sent — 



1. Cyprcea Madagascariensis, in the usual state of the species. 



2. Cyprcea staphylcea. A small, very dark-coloured variety, of 

 a uniform pale brown colour on the back, with numerous minute 

 white dots ; the base white, with yellow-edged teeth, and some 

 dark brown lines on the upper edge of the margin of each end 

 of the shell. 



I have no materials to explain the cause of this absence and 

 alteration in the usual colour of such a number of species of 

 shells belonging to a single family. As far as I have observed, 

 the peculiarities are restricted to the species of this group; 

 the shells belonging to the other families that were sent with 

 them being of their normal colour. The specimens, I may 

 observe, are of the usual size and form, and are easily deter- 

 mined by comparison with specimens from other localities. 



VII. — A Notice of Nature-Printing of Sea-weeds on the Rocks in 

 the vicinity of Stromness, Orkney. By Charles William 

 Peach*. 



I beg to lay before the Society a most interesting fact of true 

 nature-printing of sea- weeds which I met with in August 1856, 

 immediately below the ruins of the ancient episcopal palace of 

 Stromness. I was examining on the sea-shore the charnel-house 

 in which lie the skeletons of the ancient denizens of the waters 

 of the Old Red Sandstone period ; my attention was engrossed 

 by their numbers and variety, and the beauty of the sculpture 

 of the black shining wings and dermal covering of the Pterichthys, 

 the " berry upon bone" cuirass of the Coccosteus, the fluted and 

 polished spears and delicately fretted mail of the Diplacanthus, 



* Communicated by the author ; having been read at the last meeting 

 of the Royal Physical Society of Edinburgh, on the 28th April 1858. 



