200 FRESH-WATER ALG/E FROM BURMA. 



74. Euastridium Prainii sp. uniea. (PI. xiv, fig. 11). 



E. magnum, circiter lf-plo longius quam latum, profunde constrictum, sinu late 

 aperto extremo obtuso ; semicellulse trilobatee; lobis lateralibus crassis et subsemi- 

 circularibua ; lobo polari subrectangulari, eonstricto ad basin, angulis late rotundatis, 

 apice retuso; cum tumoribus magnis duobus trans semicellulas dispositis ; semicellulse 

 a vertice visa? circulares et 8-lobatse, lobis magnis regularibus et subsemicircularibus 

 lobo polari subquadrato cum angulis latissime rotundatis et lateribus concavis; semi- 

 cellula? a latere visa? nt a fronte visse. Membrana dense scrobiculata, scrobiculis 

 majoribus super lobos basales 8 et angulos 4 lobi polaris. 



Lon<'. 158-162/*; lat. 98-102/*; lat. lob. polar. 50-63/*; lat. isthm. 45/*. 



m 



J Jab. — Mansang, near Hsipaw (No. 24193). 



A number of specimens of this handsome Desmid were observed, and its characters were quite 

 oonstaut. The semicells in front view are three-lobed, the lateral lobes being large and inflated, 

 wht-reas the polar lobe is smaller and more rectangular. All the angles are broadly rounded, and 

 the ceil wall is densely scrobioulate. The scrobiculations are much larger at the angles and cause 

 the exterior of the cell-wall to be rough at those points. . The sinus is very widely open, and the 

 apex of the polar lobe is slightly retuse. Bat it is in the vertical view that this Desmid differs 

 from all others with which we are acquainted. Having a body more akin to Euastrum, it is circular 

 and 8-lobed when seen from the vertex, almost reminding one of the actinomorphic symmetry 

 exhibited by certain of the rayed species of Staurastrum. The & lobes are basal in position, corre- 

 sponding to the lateral lobes of the front view, the apical part of the cell only having 4 lobes. It 

 is this actinomorphic character which renders it impossible to place this Desmid in either Euastrum 

 or Mtcrasteria*. One of the primary characters of these genera is the compression of the cell (often 



very considerable) in the plane of the 



Burmese Desmid there is no trace 



of any such compression. We have, therefore, established a new genus — Eumiridium — to include this 

 extraordinary actinomorphic Desmid, 



* 



The front view bears some resemblance to certain species of Euastrum, but the sinus is more 

 open, and the lateral lobes shorter and more inflated than in any species of that genus. There is 

 likewise no special notch such as is present in most species of Euastrum. The only forms connecting 

 Euastridium with Bmstrum are such as E humerosum Ralfs forma triquetra Schroder (Beitr. Algen 



quite a different nature. 



lobing as seen in the vertical view is of 



Genus: Micrasterias Ag. 



75. Micrasterias foliacea Bail, in Ralfs Brit. Desm. 1848, p. 210, t # 35, f 



V 



3; Johnson, Species of Micrasterias, 1894, p. 57, t. 6, f. 1-4 



ornata Nordst. Desra. Brasil. 1870, p. 221, t. 2 f. 16 



Long. 67/*; lat. 71m; lat. isthm. 11-5/*; lat. lob. polar. 30/* (PI. xiv, fig. 22). 

 Hab.— Mansang, near Hsipaw. (No. 24193). 



The lateral lobes were less divided than in most forms of this species, and the lobules were son* 

 irregular. 



76. Micrasterias incisa Breb., 1839; in Kiitz. Phyc. germ. 1845 p 134 



Turn. Freshw. Alg. E. India, 1893, p. 89, t. 6, f. 8, 10. * 

 Rdocystis incisa Wall. Desm. Low. Bengal, 1860, p. 276 t. 13 f. 4 5 



Var. Mansangbnse var. n. (PI. siv, fig. 18) 





