200 RUESH-WA'L'EK ALGÄ; I'ROM BUHMA.
7 4 . EUASTRIDIUU PHAINII sp. u n i e a . ( P L xiv, fig. 11).
K. iiiairiuim, circiter If-plo Innsius qiinni iatuin, profunde cnnstricíuin, sinu late
apt'ito oxtreoio obtuso; seiiiicellulfe trilobatie; lobis lateralibus erassis et subsemicircularibus;
lobo polari siibrectangulari, constiicto ad basin, angiilis late rotundatis,
apice letuso; cum tunioribus uiugnis duobus trans semicellulas dispositia; aeuiicellulse
H vtiftiee visiB circulares et 8-lobataä, lobia oiagnis rogulnribus et subsemicircularibus
lobo polari subqaadrato cum aiigulis latissime rotundatis et lateribus concavis; Kemicellula;
a latere visa; ut a fronte visai. Membrana dense scrobiculuta, scrobiculis multo
niajoribus super lobos basales 8 et ángulos 4 lobi pularis.
Long. 158-162^; lut. 98-102/x; lat, lob. pular. 50-63/x; lat. istlim.
//«&.—Mansang, near Hsip.uv (No. 24193).
A numlier of specimeus of tliís liu,iidsome Desraid were observed, and its characters were quite
coiistaut. Tiie seraicells in f r o n t Tiew ar» three-lobed, the lateral lubes l e i u g large aud inllated,
whereas the jiolar luhe is smaUer aud more xeotaugular. All the augles are broadly rouuded, and
t h e cell wall is densely scTobiculate. Tha serohioulations iire uiach largor at the angles aiid cause
t h e exterior of the oell-wall to be rough at those points. The sinus is very widely open, a n d the
a p e s of the polar lobe is s l i g h t l y rotu;e. Eut it is in the vertical view that this Desmid diflers
f r om all others with which we are acquainte.i. Having a body more aliin to Etmirum, it is circular
a n d 8-lobed when seen from the vertes, almost reminding one of the actinomorphio symmetry
e x h i b i t e d b}' certain of the r a y e d species of Utaarustrum. The Ö lobes are basal in position, corresponding
to tlie lateral lobes of the front view, the apioal p a r t of the cell only haviug 4 lobes. It
i s this actinomorphic character which renders it impossible to place this Desmid in either EmUruni
or Mterasteyia^. One of the primary cliaracters of these genera is the comprcKion of the cell (often
very eousideinblo) iu the plaue of the front view, but in this n e w Burmese Desmid there is no trace
of uny such compression- We have, therefore, established a new genus—E i t m i r i i l i u m—to include this
e x t r a o r d i n a r y actinomorphic Desmid.
Tlie front view bears some resemlilance to certain species of Euasinm. but the sinus is more
open, and tbe lateral lobes shorter and more inflated than in any species of that geuus. Theru is
like-wise no special notch such as is present in most species o£ Euastrum. The only forms ccunecting
Eaas'.rldium with Buustnnn are such as E humfrosinn Ralfs forma triqueira Schroder (Beitr. A l g en
Riosengebirges, 1S98, p. 38, t, 2, f, 3), but IQ this case the lobing as seeu in the vertical view is of
q u i t e a difíerent nature.
Genus; Micrasterias ¿g.
7 5 . MICUASTERIAS FOLIACEA Bail, in K a l f s B r i t . Desm. 1848, p. 210, t, 35, f.
3; Johnson, Species of Micrasterias, 1894, p. 57, t. G, f. 1-4,
Var. OHNATA Nordst. Desui. Brasil. 1870, p. 221, t. 2, f. 16.
Lnng. (^Tfi] lat. 71/i; lat. istbm. 11-5^; lat. lob. polar. 30/t (PI. xiv, fig. 22).
]Jah.—Maiisang, near Hsipaw. (No. 24193).
The lateral lobes were less divided t h a n i n most forms of this species, and t h e lobules were somewhat
irregular.
7 6 . MICHASTEKIAS INCISA Bréb-, 1 8 3 9 ; in K ü t z . P l i y c . g e r m . 1845, p. 1 3 4;
Turn. Freshw. Alg. E. India, 1893, p. 89, t. 6, f. 8, 10.
JlnloGysiis incim WaU. Desm. Low. Bengal, 1860, p, 276, t. 13, f. 4, 5.
V a r . MANSASGHNSE v a r . n. ( P I . s i v , fig. 18).
MICRASTFRIA.?. ^
Cellula? 3 |-plo latiore.s quam longic (.^ine spinis) ; lobis lateralibus oblique subtruncatis,
aiigulis superioribu.s rotundatis, anguHs inferioribus .spina minata iiistruotis ;
lobo polari late truiicato, apice sub recto ; meiiibrana irregulariter granulata; a \-crtice
visa; paullo tumidie ad medium utrobiqiie.
Long. ; lat. (sine spinis) 40^; lat. ii^tbm. 16,^; crass.
Hol).—Mansang, near Ilsipaw (No. 24193).
The Burmese variety resembles var. Walhdnuna Tum. more than typical J/, incm owing to
t h e absence of tho sjines from (be superior angles of the lateral lobes.
77. MICRASTF.KIAS iRoriCA Nordsr. Desra. Brasil. 1870, p. 219, t. 2, f. 15.
Forma cim granuli s magnis 4 infra margin em. apicalem lobi polaris ; scmicellute
a vertice visa:; paullo robustioribus, lateribus subrectis.
Long. 111^; lat. 98^^; lat. isthm. 17-5/x ; crass. (PI. xiv, fig. 23).
nah.—Mansang, near tlsipnw (No. 24193).
78. MICKASTERIAS MOBII (Borge) W. & G. S. West, Desm. Singapore I8i)7, p.
162; Fresbw. Chloropby. Kob. Chang, 1901, p. 86, f. 3, f. 21.
Euaslrtim mrvcnsmi Ehrcnb. var. MóUi Borge, Austral. Süsswasseroblor. 1896,
p . 13, t. 2, f. 18, 19.
Var. BiJuMEysE var. n. (PI. 3Ìv, figs. 19, 20).
Semicellulffi variabiles, apice lobi polaris late et distincte retuso ; lobis lateralibus
raajoribue et oxtcnsioribus, lobulis superioribus et inferioribus rcductis (interdum
pccne obsoletis) rotuiidato-couicis ; cum tumore magno in centro semicellularum supra
isthmum et tumore minore intra lobum lateralem unuinqiiomque. Seiiiicellulas a vertice
visa) polis plus attenuatis, umbone magno et lato ad medium utrobique, tumore multe
minore pclos versus utrobique. Aviguli lobi polaris et loborum lateralum granulis iiiagnitudinis
variabilis (sa^pe masimis) praeditis.
Long. 119-123/i ; lat. 98-lOV ; lat. lob. polar. 73-79/* ; lat. istbm. 25-27^' ;
crass, bòli.
Ì7a5.—Mansang, near Hsipaw (No. 24193).
T l i i s variety varies inuoh in the angles (or processes) of the polar lobe, which are sometimes
l a t e r a l l y produocd, sometimes a h i u p t l j truncate, and also in relative depth of division of the lateral
lobes. In some specimens the lateral lobes are almost entire, and in others the superior and
i n f e r i o r laterol lobules are short and rounded. The granulation of the angles of the polar and
l a t e r a l lobes aUo varies very much. It is distinguished from typical M- Uäbii by its proportionately
g r e a t e r width across the base of the remicoUs, by the broadly retusu spex of the polar lobe, by
t h e more prominent scrobiculato tumour within each lateral lobe, and by the attenuated polc-s of
t h e vei-tical view.
M. ^bbii vnr. BurmcMo should be compared with M. Miibii var. Javanica Qutw. (Alg. Ins. Java,
1902, p. 603, t. 40, f. 58) w h i c h . i t resembles more than the type. It diSc-rs, however, in the
reduced lateral lobules, and in tbe replacement o£ the several small tumours within each lateral lobe
b y one much larger one.
The vertical view of .V. JUobii var. Burmense is almost exactly similar to that of M. 21öbU
var. Ridleui, a variety described fi-oni Singapore.
V a r . IKTKGKUM v a r . n . ( P I . x i v , 2 1 ).
A.S-ÍÍ. BOV. BOT. GARD. CALCUTTA VOL. VI.