FRESH-WATIR ALG^E FROM BURMA.
Ilah.—Mansaug, near lîsipaw (No. 24193).
St. unicorne is n very variable species, of which there are five described varieties. Turner states,
• in his description of Si. loiiconie tJiat the spine at the estremity of each angle may be curved,
s t r a i g h t , convergent, or divergent. In the specimens of S(. unkorne var. cei/lamcum described from
Ceylon the terminal spines were curved and slightly convergent.
130. STAURASTRDM CUSPIDATOSI Bi-6b. in Menegh. Synops. Desm. 1840, p. 226 ;
Ralfs, Brit. Desm. 1848, p. 122, t. 21, f. 1 ; t. 33, f. 10.
JTctJ.—Maiisang, near Hsipaw (No. 24193).
1 3 1 . STAUEÌSTK-DM PRAINII sp. u. (PI. xvi, fig. 10).
St. magnum, circiter tana longum quam latum, profunde constrictmn, sinu
angusto apicem yersus deinde estrorsum valde ampliato; semicellulaì transverse subelliptic
®, apice late truneato (iuterdum levissime retuso), angnlis lateralibus cum
mamilla parva intus ex cavata spinam brevem ferente ; a vertice visie triangulares,
lateribus in medio retusis, angulis late rotundatis apico estremo subiter et Lsviter
producto et spina brevi prsedito ; membrana glabra.
Long. 8 6 - 8 8 l a t . sine spin. 73-90/x, cum spin. 79-100/:^; iat. istbm. 26-28^.
£ab.—Mansang, near Hsipaw (No. 24193).
Tbis species difiers from i t . majmcuhim "Wolle and St. »lagmtm WoHe in being proportionately
wider, in t h e flattened apices and more inflated angles of the semi-cell-, in the much narrower
apical part of the sinus, and in the short spines which arise f r om a small hollow projection at each
angle. The inflated angles are most clearly seen in the vertical view.
I t should also be compared with St. conspicuum W. & G. S. West, from which it is distinguished
by ite relatively longer cells with more inflated lateral angles, each of which is furnished with a
short spine situated on the extremity of a hollow mamillate projection. The cell-wall is also smooth
132. STACEASTRUM BIFIDDII Bréb. in Kalfs, Brit. Desm. 1848, p. 215; Lund.
Desm. Suec. 1871, p. 63, t. 4, f. 2. ' '
Long. 31-5;^; lat. sine spin. 29-31/i, cum spin. 48-56«; lat. isthm 11'5„
(PI. xvi, fig. 7).
Uaò.—Mansang, uoar Hsipaw (No. 24193).
133. STADRASTEUM SUBTEIFUKCATUM W. & G. S. West, Some N. Amer Desm
1896, p. 258, t. 16, f. 24.
Var. MAjus nob.
Si. subtrifurcahm Schmidlo, Ost-Afrika Desm. 1898, p., 56, t. 3, f. 17.
suhtrifurcaium forma major W. & Gr. S. West, notes Alg ii 1900
p. 205. 6 - ,
Var. major, semicellulic a fronte vis® sinu apcrtiori, apice leviter retuso;
a vertice visie angulis subinflatis «t acute rotundatis, lateribus subrectis
(sed leviter retusis in medio).
Long, sine spin. 56^, cum spin. 84-86-5;.; lat. sine spin.. 54-55-5/^, cum spin
105-108/^: lat. isthm. 15;*. (PL xvi, fig. 15).
Eah.—Mansang, near Hsipaw (No. 24193).
STAUEASTEUM, 2 1 5
This variety differs f r om the type in the lower portion of the angles of the semioells being
produced, and also in the slight inflation of the angles. These features cause the vertical view to
differ oonsideiably from that of the type. In the f r o n t view the apices of the semicells are sUghtly
retuse, and the sinus is also more open. We thiul: Schmidlo's fig. 17n (Ost-Afrika Desm. t. 3) is
somewhat oblique. Sohmidle has also recorded this Desmid from the vicinity of Lake Nyassa, but
t h e figure bo gives is of a form with shorter spines (vide Sehmidle, Alg. aus Nyassa-See, 1903, p.
73, t. 2, f. 8).
Sohmidle also remarks that St. fridem-Nepfuni V7. & G. S. West (Welw. Afric Freshw. Alg.
1897, p. 177, t. 36, f. 7) should be placed as a from of St. siiblrifurcntirm, but we distinguished
i t f r om the latter species at the time of its publication. In St. tridena-Neptuni the three spines
at each angle of the aemiceUs are situated wUcalln over one another in one plane, and are shorter
and stouter. Moreover, the verlicnl view is pentaiioval with arute angles.
I n the same paper Sehmidle describes a " f o r m a bidens" of St. wbtri/urcaUm, uni this has since
been recorded from Java by Gutwinski. It seems to us, however, that the " f o r m a bidens" is much
more nearly akin to St. longtspinum (Bail.) Arch, than to St. suhtri/'ircalHvi. Tlio f o rm of the
vortical view and the presence of only two long spines at each angle, which are vertically disposed
one over the other, lend strong support to this view.
1 3 4 . STAURASTRUM DISPAE\TUM sp. n. (PI. x v i , - f i g . 5).
St. mediocre, paullo longius quam latum (aine spinis), profunde constrictum, sinu.
valde aperto et rectangulari ; semicellulaj late triangulares, marginibus inferioribus
rectis vel subrectie, apice levissime retuso (subrecto), angulis leviter bilobatis, lobo
inferiori spina valida longa subdivorgonti instructo, lobo superior! spinis binis multe
minoribus horizon taliter dispositis instructo; a rertice visje triangulares, lateiibus
levissime retusis (subrectis), angulis in spinos validos longos productis, intra angulum
uDurnquemque spinis binis parvis prope basin spinoe valid® ; membrana glabra.
Long, sine spinis 33;*; lat. sine spinis 37-29/I.; ciim spin. 52-5-6 lat. isthm.
8-6;*.
Hal. Mansang, near Hsipaw (No. 24193).
This species approaches St. Ireannnii var trisuetrum W. & G. S. West (Freshw. Alg. Ceylon,
1902, p. 177, t, 21, f. 22), but is easily distinguished by the large simple aculei at each angle,
by the triangular semicells, and by the rectangular sinus. The three pairs of small spines at
t h e apes of each semicell are also situated much nearer the angles; they are shorter than thoseof
St. Freemanii, much less divergent, and in the vertical view they do not project beyond the
margin.
135. STAUEASTKUM MANBASGENSE sp. n. (PI xvi fig. 4).
St. parvum, circiter tarn longum quam latum, profunde conptrictum, sinu
acutaneulo et aperto augustiori ad apicem : semicelluloe subtrapezoidcoe (vel lat©
truncato-pyramidata;), lateribus et apice leviter convexis, angulis basalibus et superioribuH
verruca emarginata pricditis, cum verruca emarginata ad medium marginis
lateralis uniufcujusque, etiam verrucis emarginatis duobus juxta et infra marginem
apicalem; a vertice visse triangulares, lateribus leviter convexis, angulis in verrucam
emargiratain subiter productis, serie verrucarum eroarginatarum 4 intra maiginem
lateralem unumquenique et spinis minutis geminatis prope angulum unumquomque
utrobique.
Long. 26;., ; lat. 24-5^ ; lat isthm. 7-5;^.
6.—Mansang, near Hsipaw (No. 24193).
ANN. ROY. Bor. G.-ÌRD. CALCUTTA VOL. V I .