REPORT ON THE DIATOMS OF THE ALBATROSS 

 VOYAGES IN THE PACIFIC OCEAN. Iss.s-V.m4. 



By Axbeb i Mann. 

 [Assisted in the bibliography and citations by P. L. Ricker.] 



INTRODUCTION. 



The paper here offered is a report of the diatoms found in the sea 

 dredgings and soundings of the United States Bureau of Fisheries 

 steamer Albatross, which covers all the material collected and avail- 

 able up to January 1, 1005, exclusive of what is embraced in a short 

 report already published by the author. 



The preliminary work was done in the Smithsonian Institution, 

 Washington, I). C, during the winters of 1899-1900 and 1904-5. The 

 crude material, as a rule bottled and preserved in alcohol, was first 

 examined under the microscope, using magnifying power- ranging 

 from 23 to 590 diameters, so a- to discover which gatherings gave 

 promise of affording diatomaceous material. In very many cases no 

 trace of diatoms was discoverable. The gatherings thus selected were 

 then prepared for more accurate investigation by methods that are 

 briefly described as follows: 



The mud is first passed through a sieve of bolting cloth with a mesh 

 of about one thirty-second inch, so as to strain out large pieces of for- 

 eign material, Mich as bits (^ animal tissue, fragments of shells, etc. 

 The alcohol i> then eliminated by washing in filtered or distilled water 

 in a glass beaker and decanting of the liquid after all solid material lias 

 settled. The mud is next boiled in a beaker with concentrated com- 

 mercial hydrochloric acid for one-half hour. Tin 4 acid when cold i- 

 decanted and the residue washed with water to get rid of the resultant 

 salts. The material is then boiled in concentrated commercial nitric 

 acid for fifteen to thirty minutes and again washed. This suffices in 



" Pro< . f.s. Nat. Mus. 16: 303 312. L894. 



