98 NATURAL SCIENCE. FEB., 
the Gulf Stream and the Azores, whereas the Tomopteridz 
are abundant there. He mentions an interesting form, which 
appears to be cosmopolitan, since it has been found in the 
China Sea as well; he says that several species also occur in the 
whole southern region; but for other forms he gives special districts 
of distribution. 
Finally, passing from these groups of animals, we may look 
forward with interest to the faunistic results that will be obtained in 
other groups. Some preliminary communications of morphological 
interest have also appeared (on the pelagic Anthozoa, by Van 
Beneden, and on Gastropods, by Simroth), and whatever the results 
may be regarding the uniform distribution of the Plankton in the 
open sea, though till now they agree very well with the views 
of the originator of the expedition, we may be sure that our know- 
ledge of the faunistic distribution and of morphological facts will 
undergo a remarkable extension by this expedition. 
I will not conclude this short sketch without drawing attention to 
the practical side of such an expedition, and its value for fishery 
questions in general. Though it may not appear so at first sight, 
yet, however any group of the animal kingdom may be related to 
the other groups, and however far apart some families, classes, or 
types may stand in the morphological system, they are nevertheless 
in direct physiological connection. The fishery commissioners’ task 
must be not only to observe the fishes in their occurrence and their 
wanderings, and to study their enemies and their food, but also 
to take into consideration every pelagic animal, and to calculate 
the complicated mutual relations existing between the single 
groups. 
Thus I can affirm that even the Meduse have an importance 
for the fishery questions; not as enemies of the fishes nor as their 
food, but as competitors. It is well known that small Crustaceans, 
chiefly Copepods, form the food of most fishes, and the oceanic 
Medusz, which are beasts of prey, feed on the same material. These 
Meduse are very voracious (one can often find their stomachs filled 
to bursting with Copepods) and are very bold in their movements ; 
they are well provided for the struggle for life in the open ocean, and 
since they occur in enormous quantities, they are certainly of some 
importance from the practical point of view as well. 
If we make a little step forwards in the knowledge of the com- 
plicated relations in which the inhabitants of the ocean stand to one 
another, the beast of prey and the animal it feeds on, as well as the 
plants which form the “‘ primzeval food” (Urnahrung) ; in other words, 
if we come to some understanding of the ‘‘ production and the meta- 
bolism of the ocean,” then a chief object of the expedition will have 
been attained.* 
1 Some of the first publications of Hensen’s Expedition, namely, the descrip- 
tion of the journey, &c., have now begun to appear. 
