On Oceanic Infusoria, Living and Fossil. 263 



Before dismissing the subject of microscopic vegetables, I may re- 

 mark, that the colouring of the waters of the lied Sea is now gene- 

 rally supposed to be caused by the presence of countless multitudes 

 of a minute alga, which is perfectly invisible to the naked eye, except 

 when great numbers are congregated together. Some writers have 

 denied that the water of the Red Sea has any peculiar colour, or that 

 its name is owing to the colour of its waters. Others, on the con- 

 trary, describe a red shade, of a very singular character, as present, 

 and various explanations of the phenomena have been given. The 

 differences among travellers in their account of this sea may be re- 

 conciled by supposing their observations to have been made at dif- 

 ferent seasons of the year ; for, if the colour of the water depends on 

 the presence of the vegetable matter, it is highly probable that it 

 will vary in degree at different seasons. That its waters are occa- 

 sionally coated with a scum of a red colour is certain, and portions of 

 it have been brought home and carefully examined by several na- 

 turalists. M. Montague has given an elaborate account of speci- 

 mens which he had received, and has proved that the scum is 

 entirely made up of a very minute alga, which consists of delicate 

 threads, collected in bundles, and contains rings of a red matter, 

 within a slender tube. This little plant has a structure very similar 

 to the Oscillatoriaj, which form green scums on stagnant pools ; or 

 perhaps it more nearly resembles the pretty little fresh water alga, 

 called (by the somewhat jaw-breaking name of) Aphanizomenon. 

 Minute algte of this description are by no means confined to the 

 waters of the Red Sea, but are met with in many parts of the ocean, 

 sometimes extending in broad bands for hundreds of miles. Mr Dar- 

 win, in his interesting Voyage, gives an acccount of several extraor- 

 dinary bands of this description which he met with in the Pacific 

 Ocean. I have had the advantage of inspecting some of the speci- 

 mens brought home by this naturalist. They are very similar to 

 the species of the Red Sea. — (The Sea-Side Book, by Harvey, 

 p. 174.) 



No lice of Land- Shells found beneath the surface of Sand- 

 hillocks on the Coasts of Cornwall.* By RlCHAKD Edmonds 

 Junior, Esq. 



In my Paper on the origin of our sand-hillocks, read before the 

 Society in 1846,f it is stated that in one of the deep cuttings in the 

 Towans of Phillack, within the space of a few inches, was found a 

 great number of the shells of the Hdix pulchella, a species now sol- 



* Transactioaa of the Royal Geological Society of Cornwall for 1848, p. 70. 

 Read Gtli October 1848. 



t See Jameson's Journal for July 1847, p. 181. 



