DTTBLIW NATTTBAL HI8T0HT 80CTETT. 201 



Plate I. Fig. 1, front view ; Fig. 2, end view. 



This form appears to me very distinct from any described. The 

 presence of the conspicuous pair of acute spines projecting from each 

 margin at end-view distinguishes it from all but Staurastrum vestituniy 

 but in that species the spines, which are apparent only in the end-view, 

 are emarginate at the ends, and often accompanied by others of consi- 

 derable size ; and indeed, even the smaller are themselves often emar- 

 ginate ; moreover, in the front- view it differs by its converging process. 

 It is also considerably smaller than Staurastrum vestitum^ being not 

 more than half its width, which diameter in that species greatly exceeds 

 its length. The converging processes in front- view are somewhat like 

 those of 8. cyrtocerum ; but in that species there are no spines at the 

 ends of the fronds, and the processes in end-view are not so much pro- 

 longed, and are curved in place of straight. The presence of the mar- 

 ginal spines in end-view, and the incurved, not divergent or parallel 

 processes in the front- view, distinguish this from S. paradoxum, S, gra- 

 cile, and S. polymorphum. 



Staurastrum nitidum (sp. nov.). 



Specific characters : Frond rough at the ends, with a series of papilla- 

 like granules; segments broadly elliptic; end-view triangiilar ; sides con- 

 vex, with a sub-marginal series of papillae; angles not inflated, mucronate. 



Locality : Pools near " Sugar-loaf;" rare. 



General description : Fronds about as broad as long ; segments 

 broadly elliptic, inner margin somewhat more turgid than the outer, 

 sub-mamillate at each side, terminated by a mucro, andf on the outer 

 margin rough with a series of minute papillae, otherwise smooth ; con- 

 striction forming a broad notch, with an acute angle; end-view tri- 

 angular, sides convex, with an inwardly curved sub-marginal series of 

 papillae, their summits directed somewhat towards the angles ; angles not 

 inflated, the last papilla forming a terminal mucro; endochrome in both 

 views disposed in a radiate maimer ; gelatinous investment evident 



Length of fi^nd, 1-540 to 1-535 ; breadth of frond, 1-540 ; breadth 

 at constriction, 1-1160 of an inch. 



Plate I. Fig. 3, front view ; Fig. 4, end view. 

 This, although not a complex form, owing to its brilliant and beau- 

 tifully radiately- disposed endochrome (in front- view almost in fillets), is 

 an extremely pretty species. In end-view its non-inflated mucronate 

 angles and series of papillae distinguish it, I think, from every other 

 Staurastrum. In front- view it somewhat resembles S. asperum {Brih.) 

 a, but the minute spines on the outer margin, in that species, are usu- 

 ally emarginate or cleft at the ends, or dilated, and the segments are not 

 mucronate at each angle, nor is the endochrome radiately disposed. In 

 the form in question, the convex sides, mucronate angles in end-view, 

 and granules not scattered, distinguish it fix)m S. pundulatum. I do 

 not think I need contrast it with any other species, and I believe that 

 both the foregoing forms have only to be seen, when their perfect dis- 

 tinctness would be at once apparent. 



