14 DIATOM AC 1 : 1 . 



nt in just so much less proportion. As much as can be 

 conveniently transported, say about a handful, should be col- 

 lected, and, if possible, not dried, but placed in a bottle and 

 tightly corked; or, it may have a little glycerine added to it, 

 which will prevent its drying, — for it has been found that 

 muds, and especially those from salt water, when once dried, 

 are only with difficulty broken down again so as to be cleaned. 

 The mud and slime attached to anchors, buoys, and submerged 

 woodwork, together with the scrapings from the bottoms of 

 vessels containing shells, plants, zoophytes, etc., may be sim- 

 ply dried in the sun, and then have a label attached. The mud 

 from beneath fresh water is of little value, as it rarely contains 

 any organisms of beauty; but the marine forms found in mud 

 are occasionally fine, beautiful and rare. 



Guano. This substance often contains species of diatomac< 86 

 not otherwise obtainable. It is the ammoniacal guanos alone, 

 however, which I have found to yield any great number of 

 diatomaceous forms; but there are certain guanos, of which one 

 known as " Bolivian guano " is an example, partly ammoniacal 

 and partly phosphatic, which contain some forms not otherwise 

 obtainable. Quantities of a pound or two in weight should be 

 secured, and the exact locality of the island or other place from 

 which it was obtained, together with the latitude and longitude, 

 and other information that may be collected and deemed of 

 interest, should be marked in ink upon the label. 



Shell Cleanings. The sand, mud, alg;o, zoophytes, and sim- 

 ilar matters adherent to marine shells, which are commonly re- 

 moved by students of conchology, have often been found to 

 yield rich harvests of rare forms of diatomacese. Such material 

 can be washed, or, still better, scraped off of the living or dead 

 shells (the dirtier such shells seem the better, of course), placed 

 in paper and plainly labeled with the exact locality, and, if 

 possible, name of the shell and depth of water from which it 

 was taken. Conchologists will do well to save all their shell 

 cleanings for this purpose. 



Marine Invertebrate. Specimens of the entire animal, or the 

 contents of the stomachs of echinoidea (sea urchins) and 

 holothuroidea (sea cucumbers), should be secured, as it has been 

 found that many, if not most of them, are vegetable feeders, 



