COLLECTING DIATOMS. 3 1 



timber has remained for any length of time afloat before shipping, 

 the logs are almost sure to have traces of Confervas, either fresh water 

 or marine, growing on them, and these, on being carefully scraped off, 

 will, in all probability, yield diatoms to reward the collector. Some of 

 the logs from the St. Lawrence or the Ottawa will yield us American 

 forms, while logs from Dantzig will give us interesting gatherings from 

 the Vistula and the interior of Poland. 



"Should a vessel be unloading " Kaurie spars" from New Zealand, 

 or some of those gigantic " sticks " which have lately been imported 

 from Vancouver's Island, we may probably be rewarded by finding 

 beautiful Antipodean forms of Diatomaceae on the former, and the 

 exquisite Arachnoidiscus or Triceratiuin IViikesii from the latter perhaps 

 even Aulacodiscus Oregonus. 



" Let us not go past these mahogany logs landing from Mexico or 

 Honduras, as the case may be, without casting an eye over them, for 

 these may have been rafted for some time in the sea before ship- 

 ment, or may have brought down new or little known forms from the 

 interior of Central America. Here, on the first log we examine, is a 

 copious incrustation of a form either identical with or closely allied to 

 Melosira nummuloides, abundant likewise in our docks. The gathering 

 is so copious that it fairly glistens in the sun. 



"Let us also scrape away some of the shelly incrustation of Ba/anus, 

 which completely covers some of the logs, for possibly among this we 

 may find that exquisite American form Terpsinoe musiea, so called, I 

 suppose, from the costal appearing like so many musical notes. 



" Here are some fishermen just coming in. Let us examine their 

 nets, for these men are trawlers, and have been fishing in deep water, 

 and the meshes of their nets may still have diatom-bearing Algae 

 attached to them. On such Algae we may probably find Rhabdonema 

 arcuamm or Adriaticum, Grammatophora serpentina and marina, with 

 species of parasitic Synedras ; possibly the singular Synedra undulata 

 may reward our search. 



" Some of the oyster shells from deep water are worth examin- 

 ing for marine Algae, or, what is even better, the greenish, leathery- 

 looking ascidians attached to them. The ascidians are regular feeders 

 on diatoms, and their stomach contents often yield a rich harvest of 

 deep-water forms difficult to obtain in any other way. Perhaps we 

 may be securing the rare Biddulphia regina, at any rate Biddulphia 

 Baileyii and aurita. We will take some for future examination, for 

 the curious Rhizosolenia styliformis is almost sure to be there. 



