Fresh-water Algse, &c. Btj A. W. Bennett. 11 



Frond moderately large, tlie shape of X. fascieulatum; each 

 frustule elliptical or slightly hexagonal, 80 /j, long by 40 fx deep ; 

 isthmus 60 /m. Each frustule furnished with four pairs of geminate 

 curved spines about 25 yu- long ; the whole of the rest of the edge 

 ciliated with closely set spines or teeth, in one specimen about 

 12 yL6 long, in another specimen much shorter. Endochrome very 

 granular, with a lighter less granular portion in the centre of each 

 frustule. 



Stream between Codale and Stickle Tarns, at an elevation of 

 about 1800 feet. Eesembles X. fascieulatum in general outline, 

 the length and breadth of the frond being almost exactly the same ; 

 but the constriction between the frustules is much less deep, and 

 the secondary spines seem sufficient to establish it as a distinct 

 species. 



Staueastrum bullosum n. sp. Figs. 18-20. 



Frond moderately large; each frustule elliptical, more than 

 twice as long as broad ; 85 fi long, 38 /j, wide, triangular in front 

 view, united by a narrow isthmus 85 /x wide. Each frustule with 

 a hemispherical projection which is very conspicuous, especially on 

 front view. Frond and projection uniformly verrucose. Both 

 frond and projection fringed with colourless equidistant unbranched 

 subulate spines. 



Among moss in stream flowing out of Loughrigg Tarn, and 

 elsewhere, apparently frequent. In outline and the equidistance of 

 the spines, and in the triangular front view, this beautiful species 

 is distinctly a Staurastrum, but it is double the diameter of S. 

 teliferum, which it most nearly resembles. The hemispherical pro- 

 jection on each frustule, which is remarkably conspicuous, seems to 

 indicate an affinity with Xanthidimn, some species of which it 

 closely resembles in general appearance. 



Staurastrum dejectum Breb. Forms a and 7. 

 „ Dickiei Kalfs. 



„ muticum Breb. 



„ . muricatum Breb. 

 „ hirsutum Ehrb. 



„ teliferum Ealfs /3 convexum n. var. Figs. 



21-23. 



One of the commonest Staurastra in moor pools. I am 

 unable to distinguish it from Ealfs's species except by the sides 

 being slightly convex, and therefore regard it as a variety of 

 that species, which both Kalfs and Wolle describe as having con- 

 cave sides on front view. The spines are much stouter and less 

 numerous than in S. hirsutum. The process of division of this 

 species is extremely interesting, and presents one of the most rapid 



