156 Coccoliths and Coccospheres. 
at least 50 /i., so that it isonly when the meshes become partially blocked 
that the organisms are caught at all. It is also clear that the treat¬ 
ment which the organisms receive in the nets is very likely to cause the 
destruction of any flagella or pseudopodia which they may possess; 
to these two factors was due the scantiness of our knowledge. What 
was wanted was a more satisfactory means of capture, so that the 
organisms might be observed unaltered and in the living state. Such 
a means has lately been discovered by H. Lohmann, 1 and by its 
means he has been able to settle the much disputed question of their 
systematic position. His ingenious method consists in taking 
advantage of the natural filtering apparatus possessed by the 
Appendicularias. The apparatus can be removed from the animals 
under the microscope, when there are found entangled in its meshes 
a large number of Protozoa and Protophyta. Under these 
conditions Lohmann was able to observe Coccospheres in a 
living condition and to observe the presence of one or two yellow 
or green chromatophores and of one or two flagella. From 
these observations it is clear that the group formerly known 
by the name of Coccosphaeraceae must be considered to belong to 
the Flagellata, and it is placed by Lohmann in the division 
Clirysomonadina of that group. He points out that Wallich’s genus. 
Coccosphaera, which formerly gave the name to the group, must be 
dropped on account of the use, for another organism, of that name 
by Perty in 1852 , in an obscure paper. He proposes instead, the 
name Coccolithophora, and terms the group the CoccoUthophoridac. 
Lohmann shows, by means of suitable methods of filtration, that the 
organisms are much more common in the upper layers of the sea (at 
least in the Mediterranean, in which his investigations were carried 
on) than was formerly supposed, and that they play an important part 
in general marine metabolism, though their numbers of course cannot 
be compared to those of Diatoms or Peridineae. He describes eight 
genera and 22 species, though previously only three genera and 5 
species had been known. All the forms are marine, and all are 
characterised by the formation of a calcareous skeleton, consisting 
of plates of very various shapes; in the majority of the forms, also, 
one or two usually yellowish chromatophores were to be observed, 
and one or two flagella, so that the group is a sharply marked one 
among the Flagellata. Very interesting results will, no doubt, be 
obtained by the use of similar methods in other marine areas. 
1 II. Lohmann, “Die Coccolitliophoridae, eine Monographic 
der Coccolithen bildenden Flagellaten, Archiv fur Protisten- 
kunde.” Bd. I., 1902. 
