Jheringula paulensis, a new generic Type of Macrothricidæ. 25 



by rhythmical strokes of its powerful antennæ, resembling 

 in this the species of the genus Macrothrix : but these 

 swimming movements, at least of the females, are far from 

 being so vivacious and incessant as in the above-named genus. 

 The males, however, as is usually the case, are rather more 

 active than the females, swimming about with great speed 

 in pursuit of the females. 



Their nourishment seems essentially to consist of vegetable 

 matter, and in accordance therewith, the contents of the in- 

 testine exhibit, at least in the anterior part, a more or less 

 greenish hue, changing in the posterior part to a dark brown. 



Occurrenc e. — The dried material from which this form 

 was raised, consisted chiefly of remains of aquatic plants, 

 with a small quantity of adhering mud. This material was 

 collected by Dr. H. v. Jhering in the neighbourhood of Sao 

 Paulo, and apparently from 2 different localities, to judge 

 from the nature of the plants. One of these samples, re- 

 ceived on the 6th July, 1898, consisted almost exclusively of 

 rush, the other, received on the 24th August, 1899, of more 

 grass-like plants. From both these samples, a number of 

 other Entomostraca were also raised; but the present form 

 was by far the most frequent and most reproductive. 



