1 TURBELLARIA. 



Polycelis nigra from Finland would correspond to P. brunnea^ 

 Johnst. with regard to the shape of the fore-body; but as for 

 the colour and the elliptical shape of the body to P. felina, Johnst. 



While keeping up some specimens of Gasterosteus in a 

 small subsaline aquarium I once let a specimen of Planar! a fall 

 into the water. In the same moment one of the fishes snap- 

 ped at the animal, but immediately left it again and from se- 

 veral movements of his body I understood that the contact 

 with the animal might have been very disagreeable to him. 

 Since that time none of the fishes showed mind to touch such 

 an animal. 



