488 PHYSICAL GEOGRAPHY. 



forms occurring at a particular station. Then, again, the fossil as well 

 as the semi-fossil deposits and guanos may be cleaned and mounted as 

 obtained ; but even then it may become desirable, if space can be spared 

 in the cabinet, to have the various species found in each gathering sepa- 

 rately mounted, so that they may be at any time studied in comparison 

 with similar forms from other localities. 



General directions for collecting diatomaceae have been already given 

 in Part Seventh ; but it will be desirable to again allude to a few points 

 in connection with this portion of our subject. Some years since, an 

 article entitled " Hunting for Diatoms " was published in a London 

 journal called The Intellectual Observer. The author's name was not 

 given, but internal evidence would seem to indicate that it was penned 

 by a deceased botanist of note, who was a decided authority on this 

 branch of biology. This paper contains some valuable hints respecting 

 the places in which to look for diatoms, and some of the suggestions 

 contained therein I have ventured to transfer to these pages, as they will 

 be found of value to the intending diatomist. Thus, the exquisite Arach- 

 noidiscus, Triceratium Wilkesii, and Aulacodiscus Oregonensis, may be 

 looked for on logs of wood which have been floating in the sea, and 

 imported from New Zealand, or Vancouver's island. So, on logs from 

 Mexico and Honduras may be found the curious Terpsince mnsica. The 

 nets of fishermen, especially from deep water, may yield algae bearing 

 such forms as RJiabdonema arcuatum or Adriatium, GrammatopJiora 

 serpentina and marina, various Syncdras, and other fine forms. On 

 oyster shells may be found algae bearing upon their fronds Biddulphia 

 regina, B alley ii or aurita. RJiizosolenia styliformis is said to be almost 

 sure to be there likewise. After a ship is unloaded, and as it floats 

 higher in the water, its sides may be searched for treasures of the diatom 

 world, and AchnantJies longipes and brevipes found, or even Diatoma 

 hyalinum and Hyalosira delicatula. The sea-grass, or Zostera marina, 

 growing along our coast, often bears upon its waving ribbons fine forms 

 of diatoms, and that used for stuffing chairs, and lounges or mattresses, 

 and imported from abroad, will yield foreign species to the collector. 

 There is a plant known in England as "Dutch rushes," which is imported 

 into that country from Holland, and which is used for chair bottoms. 

 These plants grow in the brackish water of the marshes, and hence upon 



