CATHYPNA BRACHYDACTYLA, AND ON A NEW BRACHIONUS. 373 



liead considerably through the wide frontal opening of the lorica ; 

 he has also seen a red eye over the anterior part of the large 

 mastax, which I have been unable to find in the preserved and 

 retracted specimens. 



The stomach and intestine lie on the right side, and the ovary, 

 with large nuclei, on the left side of the body cavity. 



The size of the three specimens which I have seen measured 

 yj-g- in. (150 /t) in length, ttJ^ in. (llS/i.) in width, and the toes 

 .6^5 in- (^0 /x) long. 



Stenroos's animals appear to have been a little larger namely, 

 174 /x long, 135 /x wide and the toes 34 /x long. 



Brachionus spatiosus sp. nov. (Plate 13, fig. 2). 



This striking form I found in plankton material collected by 

 Professor E,. T. Young in the Devil's Lake, North Dakota, in 

 July 1910, associated with three other rare Eotifers namely, 

 B. satanicus, Pedalion fennicum and Asplanchna Silvestrii. 



As will be seen from the figure kindly made for me by 

 Mr. A. R. Hammond, the lorica is very wide posteriorly, twice to 

 nearly three times as broad as the anterior i-egion, giving the 

 animal a peculiar and characteristic triangular form. Young 

 animals are not quite so broad in proportion. The six occipital 

 spines (Fig. 26) are of the peculiar saw-tooth pattern as met w^ith 

 in B. Midler i., but considerably larger in size. The scalloped 

 pectoral edge has four rounded, slightly irregular projections 

 as shown in the figure. The posterior corners of the lorica are 

 rounded off, and the foot-opening has thickened edges, is square 

 dorsally and pointed and V-shaped ventrally. 



As a whole the lorica is roomy, high and rounded dorsally 

 and nearly flat ventrally, similar in these respects to that of 

 B. MuUe7'i. Like the latter, B. spatiosus is a brackish water 

 form, for the water of Devil's Lake is distinctly brackish, w-hich 

 no doubt also accounts for the fact that it contains but few 

 species of Rotifers, and no distinctly fresh-water forms, at least 

 as far as the investigation of its fauna has extended. 



The lorica is thin, transparent and free from stipples and 

 posterior spines. The internal organs are quite normal ; the 

 foot is fairly long and wrinkled, with the usual two toes. 



In shape and appearance the nearest forms are probably 



