144 ^ CENTURY OF PROGRESS IN THE NATURAL SCIENCES 



also erected an order Phaeochrysidales which included organisms with two later- 

 ally inserted flagella; this group was subsequently shown to belong to the 

 Cryptophyceae. ) 



In various later contributions Pascher (1912a, 1913a, 1914, 1925b, 1931) 

 elaborated upon his classification of this group. In addition to his three original 

 orders, he established among others the orders Rhizochrysidales, Chrysocapsales, 

 Chrj^'sosphaerales, and Chrysotrichales to receive the amoeboid, palmelloid, coc- 

 coid, and filamentous types, respectively. As is true of the Xanthophyceae, the 

 bulk of our knowledge of the Chrysophyceae has been acquired during the past 

 forty years, mostly through the investigations of Pascher. At the time of his 

 death in 1945 he was engaged with a monograph on the group, which was to have 

 appeared as a volume in Rabenhorst's Kryptogamen-Flora. . . Through his death 

 phycology has lost its foremost student of the Chrysophyceae and the present 

 gap in organized knowledge of this group of algae may remain unfilled for a 

 long time. For an autobiography and bibliography of Pascher, see Pascher 

 (1953). 



In addition to Pascher, various authors (Lohmann, 1902; Scherffel, 1911, 

 1924, 1927; Petersen, 1918, 1929; Doflein, 1922, 1923; Schiller, 1925a, 1925b, 

 1930; Conrad, 1914, 1926, 1927, 1928, 1933; Kamptner, 1928; Gemeinhardt, 1930; 

 Vlk, 1938; Huber-Pestalozzi, 1941; and others) have made significant contribu- 

 tions to knowledge of the Chrysophyceae during the present century. Petersen 

 (1918, 1929) and Vlk (1938) have investigated the structure of the flagella. 

 Scherffel (1911, 1924), Korshikoff (1929), Pascher (1916a, 1917, 1930b) and 

 others have brought to light abundant evidence pointing to a relationship be- 

 tween various colorless flagellates and certain pigmented Chrysophyceae. Huber- 

 Pestalozzi (1941) has contributed a great deal to knowledge of the freshwater 

 planktonic forms but his work is of less value than it might have been because 

 of the omission of a bibliography. 



Brief mention should be made of the main steps in the growth of knowledge 

 concerning the Coccolithophorineae and the Silicoflagellatophycidae which are 

 now generally regarded as Chrysophyceae but have an interesting history of 

 their own. 



COCCOLITHOPHORINEAE 



The history of our knowledge of these organisms begins with Ehrenberg 

 (1836, 1839) who discovered in cretaceous deposits large numbers of circular 

 and elliptic carbonate disks, wliich he believed had an inorganic origin. 



New information as to the origin of these bodies was not forthcoming until 

 the survey work in the North Atlantic preparatory to the laying of the first 

 cable between Europe and America. Huxley and "VVallich found in the ooze 

 brought up from the sea bottom many carbonate bodies that resembled the disks 

 of Ehrenberg. Huxley (1858), like Ehrenberg, believed the disks had an inor- 

 ganic origin, and because of their resemblance to Protococcus cells he named 

 them coccoliths. 



In addition to many coccoliths, Wallich (1860a, 1861) also found in the 

 ooze spherical bodies to whose surface adhered such coccoliths. He regarded 

 the spherical bodies as cells of living organisms and the chalk disks as part of 



