PLANKTON OF THE WOODS HOLE REGION 
163 
P 
U 
< 
3 
bO 
p. 
CO 
+» 
u 
o 
> 
o 
s 
o 
a 
1893 
1895 
1896 
1898 
1899 
1900 
1901 
1902 
1904 
1905 
1906 
1907 
tively coarse and both ends were broken. Lohmann gives 17 mm. as the average 
length of the "Haus" of Oikopleura alhans Loeck. It is difficult to understand 
how copepods could be induced to enter such a small opening. Possibly, as in 
0. alhans, the complete "Haus" is made up of two compartments — one of coarse 
and the other of fine mesh. The currents of water produced by the movement of 
the animal's tail cause microorganisms to collect in the fine mesh. This rich food 
center may attract 
the copepods, which 
crowd into the outer 
opening. The re- 
moval of the soft 
parts of the copepods 1894 
was no doubt the 
work of protozoa. I 
have observed them 
completely clean out 
a decapod megalops j^ggi^ 
in two days. The 
difl^icult thing to im- 
agine, however, is 
how so many cope- 
pods could get into 
such a small amount 
of space. Lohmann 
found that a new 
"Haus" is secreted 
every six hours. 
This fact accounts ^903 
for the great ntmiber 
taken. 
Only one species 
{Oilcopleura longi- 
cauda (Vogt), listed 
by Pratt as Appendi- 
cularia longicauda 
(Vogt), has been re- 
corded from the 
region. Neither 
member of the genus taken this year contains the "Kapuze" characteristic of 
Pratt's species. The winter form agrees very closely with, and probably is, 0. varir 
Jioffeni Lohmann, while the summer form has many of the characteristics of 0. dioica 
Fol. At the time lack of sufficient literature prevented a final determination, and 
the preserved forms are not in a sufficiently good state of preservation to be iden- 
tified positively. 
iiiii 
Fig. 64.— Occurrence of Appendicularia during successive years. No record was made 
after 1904 
