162 C. F. ROUSSELET ON THREE NEW SPECIES OF ROTIFERA. 



In general appearance the lorica is boat- shaped, with a sub- 

 rectangular opening in front and a smaller opening posteriorly. 

 The frontal edge is bilobed, the mental edge straight, and 

 the whole anterior edge is finely serrated. The dorsal plate is 

 arched, whilst the ventral plate is flat and smaller, and over- 

 lapped by the dorsal plate. A side view enabled me to see that 

 the ventral plate is quite separated from the dorsal plate, or 

 probably connected with it by a flexible membrane. The entire 

 lorica is finely stippled all over. 



The living Anuraeoj)sis navicida has not been observed, as only 

 preserved material was available. The size of the lorica is 92 /x 

 (~^ in.) only ; thus it is one of the smallest species of Rotifera. 



I am indebted to Mr. A. Hammond for the accompanying 

 figures, which give a very good idea of this animal's appearance. 



2. Brachionus satanicus sp. nov. (PI. 7, Fig. 2). 



The difficulty of finding new and suitable names for new 

 species of Kotifera is becoming more and more acute, so the 

 above may be excusable and not inappropriate for a Brachionus 

 which inhabits the Devil's Lake in North Dakota, U.S.A. I 

 have little doubt, however, that it is a very gentle and inoffensive 

 creature, like all the members of this genus. 



The shape of B. satanicus, as shown in Fig, 2a, is very 

 remarkable, and unlike anything known. I found this new 

 species in some plankton material collected in the above- 

 named lake and sent to me by Prof. R. T. Young, of North 

 Dakota University. 



The lorica is much compressed and nearly flat, sub-quadrate 

 in shape, narrowest in front, widening posteriorly, where it is 

 prolonged into two stout and long, symmetrically curved spines, 

 equalling the lorica in length. Anteriorly the dorsal edge has 

 six very small, nearly straight spines, the middle pair being 

 slightly larger than the others, with a rectangular sulcus between 

 them. The mental edge has four distinct spines, the shape of 

 which is best shown in the figure (Fig. 26). The foot-opening 

 is simply a wide transverse slit between the dorsal and ventral 

 plates, without projection of any kind. 



It may be necessary for me to say that this new species has 

 no affinity to B. Bakeri, or any of its numerous varieties. The 



