MASKELii. — Oil New Zealand Desmidiese. 25 



particulars, mainly iu the arrangement of the spines. The 

 triangular end-view of our species is scarcely a distinctive 

 character, as so many of the Staurastra seem to have indif- 

 ferently three or four sides. 



Staurastrum sinmiliferum, sp. nov. Plate Y., fig. 44. 



Frond moderate ; constriction shallow, wide ; segments iu 

 end-view inflato-fusiform, widening rapidly from the isthmus 

 to the angles ; ends convex ; angles acute ; cytioderm bearing 

 minute puneta arranged in transverse rows, and towards the 

 angles very minute spines ; many very minute spines along 

 the edges all round, and at each angle three spines rather 

 larger. End-view triangula,r; sides straight or shghtly con- 

 cave; cytioderm punctate ; spines as in front-view. 



Long., 34 /a; lat., 26-9 /u,. 



Hawke's Bay. 



Probably of the series of which S. liirsutum, Ehr., is 

 the type ; but it differs in its acutely -angled front-view from 

 all, and the spines are also much smaller than in any species 

 described. Indeed, only careful examination will detect them. 

 I have stated above that in front-view these spines are notice- 

 able on the surface towards the angles, the median space 

 being simply punctate : it may be that the spines cover the 

 whole frond, but they are too minute to be made out. Mr. 

 Turner suggests that the plant maybe a form of S. hjelimanni, 

 Wille, which has minute conical granules on the edge ; but in. 

 our species they are certainly fine spines. 



Staurastrum pseudassurgens, sp. nov. Plate V., fig. 45. 



Segments in front view widely dilated from a rather narrow 

 isthmus, with gaping constriction ; lower edges very slightly 

 crenulate, outer edge crenulate, convex, with a series of 

 minute granular verrucas just within the edge ; segments pro- 

 duced at each side into siab-cylindrical processes, each of 

 which curves gradually but conspicuously upwards, and ends 

 in two rather large teeth, widely thverging, one tooth turned 

 well upwards, the other usually horizontal or nearl}' so. 

 End-view fusiform, slender, the median portion slightly dilated, 

 the rows of verrucas visible ; two terminal teeth usually 

 visible, but often only one. Zygospore sub-globose with con- 

 cave edges, bearing a number of long rays which are forked 

 and recurved at the apex. 



Long., 29-32 /i,; lat., 46-50 /x; diain. zyg. ex rad., 27 /x ; 

 long, rad., 12 /x. 



Kutherford's Swamp, Otaki. 



I at first considered this plant as S. assurgens, Nordstedt, 

 having then only a sketch of the latter. I find, however, that 

 it differs, first in size, secondly in less slender shape, thirdly 

 in never exhibiting more than two teeth on each process. In 



