CORRIGENDA ET ADDENDA. 603 



"The Ascidians found attached to oyster shells and 

 stones from deep water have yielded excellent gatherings. 



" The Salpse often noticed in warm latitudes floating on 

 the surface of the sea, and assuming chain and other like 

 forms, should be bottled up for examination. These SalpaB 

 are well known Diatom feeders. 



" Deep-sea soundings ought to be preserved, especially 

 from great depths, and are often exclusively Diatomaceous. 

 Sea-weed from rocks ought to be preserved, especially the 

 smaller species, and if covered with a brown furriness, so 

 much the better. 



" Very rare species have been found in immense quan- 

 tities in the ARCTIC and ANTARCTIC regions, by melting the 

 ' pancake ice] which is often found discoloured of a brown 

 tint, in consequence of the great numbers of these minute 

 beings. 



' ' The sea is often observed to be discoloured by brownish 

 patches. The discoloured water (or ' spawn ' as it is called) 

 should be collected, filtered through cotton wool, and the 

 brown residue preserved. 



" When a fine impalpable dust is observed to be falling 

 at sea, it ought to be collected from the folded sails and 

 other places where it lodges. This may yield Diatomacese, 

 which from the method of collecting would be highly 

 interesting to examine. 



" The roots of the various species of Mangrove (Rhiza- 

 phora), which form impenetrable barriers along the salt 

 water rivers and estuaries in the tropical parts of Africa, 

 Australia, the Eastern Archipelago, &c., are found fre- 

 quently covered with a brown mucous slime very rich in 

 Diatomacese. 



" When the Diatomaceae are collected from any of the 

 above-mentioned sources, they may be at once transferred 

 to small bottles, or the deposit may be partially dried and 

 wrapped up in pieces of paper or tinfoil. When placed in 

 bottles, a few drops of spirits added will keep them nice 

 and sweet. 



" In all cases it is essential to keep the gatherings 

 separate and distinct, and that the locality whence obtained 

 be written on the package. 



"All shells and stones from deep water which are 



