576 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



which I owe to these are ah-eady embraced in my monographs on these 

 three classes in the Challenger Eeport, and in the preface I have ex- 

 jiressed to Gapt. Eabbe my sincere thanks for his very vahiable aid. 



Of all expeditions which have been sent out for investigating the 

 biology of the ocean, that of the Challenger was, without doubt, the 

 greatest and the most fruitful, and I recognize it with additional grati- 

 tude since I was permitted for twelve years to take part in working up 

 its wonderful material. When, after the return of the expedition, I was 

 honored by its leader. Sir Wyvillc Thompson, by being summoned to 

 work up the extensive collection of radiolaria, I believed, after a hasty 

 survey of the treasures, that I could complete their investigation in the 

 course of three to five years; but the further I proceeded in the inves- 

 tigation the greater seemed the assemblage of new forms (4, p. xv), and 

 it was a whole decade before the report on the radiolaria (part xviii) 

 was completed. Three other reports were also then finished — on deep- 

 sea horny sponges (part lxxxii), on the deep-sea medusiT3 (part xii), 

 and on the siphonophores (part xxviii) collected by the Challenger. 

 The comparative study of these extremely rich planktonic treasures 

 was highly interesting and instructive, not only on account of the daily 

 additions to the number of new forms of organisms in these classes, 

 but also because ray general ideas on the formation, composition, and 

 importance of the plankton were enriched and extended. I am sin- 

 cerely thankful for the liberality with which Sir Wyville Thomi^son, 

 and after his untimely death (1882) his successor. Dr. John Murray, 

 placed these at my entire disposal. 



A record of the 168 stations of observations of the Challenger ex- 

 pedition, whose soundings, plankton results, and surface preparations 

 I have been able to investigate, has been given in § 240 of the report 

 on the radiolaria (4, p. clx). The number of the bottles containing 

 plankton (from all parts of the ocean) in alcohol amounts to more than 

 a hundred, and in addition there are a great number of wonderful 

 preparations which Dr. John Murray finished at the different obser- 

 vation stations, stained with carmine and mounted in Canada balsam. 

 A single such preparation ^for example, from station 271) contains 

 often 20 to 30 and sometimes over 50 new species. Since the material 

 for these preparations was taken with the tow net, not only from the 

 surface of all parts of the sea traveled by the Challenger, but also from 

 zones of different dej^ths, they make important disclosures in morphol- 

 ogy as well as in jihysiology and chorology. To the study of these 

 station preparations I am indebted for many new discoveries. I have 

 been able to examine over a thousand (4, p. 16). 



If I here refer to the development and extension of my own plankton 

 studies, it is because I feel compelled to make the following brief sum- 

 mary of results. I am not now in a position to give the proofs in detail, 

 and must defer the thorough establishment of the most weighty 



