1 8 8 FEESII-WAÏER ALG/LI FROM BURMA.
2 4 . MOUGEOTIA PAKVDLA H a s s . , 1 8 4 3.
Mcsocarpus parvulm Ilass. B r i t . F r c s b w . Alg. 1 8 i 5 , p . 169, t. 45, fîgs. 2 - 3;
D e B a r y , C o n j . 1858, p. 80, t. 3, f. 15.
V a r . ELLiPSOiDEA vav. n. ( P l . s , figs. 14, 15).
V a r . s p o r i s t r a n s v e r s e r h o m b o i d e o - c l l i p s o i d e i s.
C r a s s . cclL v e g e t . 9 - 6 - 1 I ' 5 / í ; l o n g . s p o r . 2 7 - 2 8 ; ^ ; l a t . s p o r . 2 1 - 2 3 / i.
Ilah Mansang n e a r H s i p a w (No. 2 4 1 9 3 ).
2 5 . MOUGEORIA PRODUCI'A sp. n. ( P l . x, figs. 1 6 - 1 9 ).
M. c e l l u l i s v e g e t a t i v i s d i á m e t r o 1 2 - 2 0 - p î o l o n g i o r i b u s j spora3 q u a d r a t a î , l a t e r i b ua
c o D c a v i s vel l e v i s s i i n e c o r i v e x i s , SDguiis p r o d u c t i s et t r u n c a t o - o b t u s i s , seepe t o r t oe c um
a n g u l i s duobiis in p l a n i t i c p e r p e n d i c u l a r i t e r d i s p o s i t a ad p l a n i t i e m a n g u l o r i i m d u o r um
a l t c r i o r u m ; a p l a n o s p o r a ; o b l i q u e t l o l i f o r m c s a p i c i b u s ] ) r o d u c t i s trun c a t o - o b t u s i s : memb
r a n a spora; p u n c t a t a , f i r m a sed t e n u i o r i ad á n g u l o s.
C r a s s , coll. vogot. T-S/^; lat. spor, long, a p l a o o s p o r , 3 3 - 3 7 / í;
l a t . a p l a n o s p o r , 1 7 - 1 8 ^.
I l a J ) In a d i t c h at t h e s i d e of salt w o r k s , V i z a g a p a t a m (No. 17916).
M. producía is obaracterized by its peculiar spore.?, wMoli ate quadrate ia furni witli produced
augles. The augles arc subtruEcate, and the spore-wall, wliioli is of the normal thicl.ness everywhere
else, is very thin at these points. This is the reverse of the usual oonditioo in which the wall is
thickened at the angles.
I t is most nearly allied to M. viridis (Kiitz.) Witfcr., but différa from that species in its longer
vegetative oeUs. and in the produced, Ihin-icalled angles of the spores.
T h e plants observed were of special interest, because of the pressnoe of aplanosporea in no way
difierent from those which aro found iu the genus Gonaionetna. These spores were formed from the
contents of one cell only, and were obliquely harrel-shaped with produced poles. The wall of the
aplanospore was of exactly the same character as that of the spore which results from conjugation,
t h e truncate extremities of the angles being very thin. Not only were these asaxual spores being
formed in filaments not otherwise oonoerned in spore-formation, but they were similarly produced in
filaments which were also taking part in conjugation (PI, x, fig. 16). Au aplanospospore oould
f r e q u e n t l y be observed nest to a quadrate epore, which latter was the result of the conjugation of
t h e adjoining cell with a cell of another filament. Thus the characters of the two genera Mougeotia
and Gonaionema are here combined in the same species, and can be observed in different parts of
t h e same filament.
"Wittrock has described and figured apl anos pores in Mougeotia calcarea {aide Witti-. Gotl, 01. sot v.
Alg. 1872, p. 42, t. 2, figs. 7, S). These spores were out oG f r om the sterilo cells by the format
i o n of new cell-walls in a manner strictly comparable with the method of formation of the spore
produced as result of conjugation, and we have regarded their formation as due to the stimulus which
h a d ab'eady caused conjugation to take place in another portion of the same filament (W. & G. S.
West, Ohs. on Conj. 1»98, p. 38). The aplanospores of Mougeotia producto may be of this type,
b\it they are commonly produced in filaments which are not conjugating in any part of their length.
So far aa could be judged from preserved material, the spores much resembled those of Qonaionema
ventricosum "Wittr. and most probably orginated in a similar manner.
Movgeotia producía is of special interest, as it shows that although apianospore-formation is the
sole type of spore-formation in Gonatonema, yet it may go on abundantly in a 3[ougeolia along with
spore-formation as a result of conjugation ; and if both types of epore-formation are shown to exist
i n other species of Mougeotia, it may be necessary to place GonatoncTna merely as a section of the
g e a u s Mougeotia in which spore-formation resulting from conjugation has ceased to exist,
CYI.,INDNOCYSTIS. 1 8 9
Certain of the aplanospores of M. prodacta possessed peculiar aiinular thickenings around their
produced poles. One of these spores is figured on PI. x (fig. 18).
S t e r i l e s p e c i e s of Mougeotia were o b s e r v e d f r o m V i z a g a p a t a m (No. 17916) a nd
K a j a u k t a g a (No. 2 2 1 2 4 ).
F a m i l y : D E S M I D I A C E J E -
G e n u s : Gonatozygon De B a r y.
2 6 . GONATOZYGON MONOTIENIUM De Bai-y in R a b e n h , à l g . 1856, No. 5 3 9 ; \V.
& G. S. W e s t , B r i t . Desm. 1904, p. 30, t., f. 1 - 7 ; t. 5, f. 5.
G. Ralf sii De B a r y , C o u j . 1858, p. 76, t, 4, f. 2 3 - 2 5.
L a t . cell. 9 - n - D U.
2 / a i . — M o m a u k , e a s t of B h a m o ( N o . 3 1 5 5 1 ) , M a n s a n g n e a r H s i p a w ( N o . 2 4 1 9 3 ).
B e t w e e n T h i n g a n - n y i - n a u n g and K a w k a r e i k , iu the side c h a n n e l of a s t r e am
( N o , 2 4 4 8 3 ).
V a r . x'lLosELLUM N o r d s t . in W i t t r . & N o r d s t . A l g . E x s i c . 1886, No. 7 5 0;
f a s e . 21, p. 4 8 ; W. & G. S, W e s t , 1. e. p. 31.
F o r m a M i n o r . Long. cell. 120/:^; lat. 5-5/j,.
Hah.—Mansang near H s i p a w ( N o . 2 4 1 9 3 ).
2 7 . GONATOZVGOÌJ KINÌHANI ( A r c h . ) R a b e n h . F i o r . E i i r o o - A l g . iii, 1868, p. 1 5 6;
W. & G. S. W e s t , I c. 1904, p. 35, t. 2, f. 1 - 3.
L a t . cell. 1 3 - 1 4 ^.
/ 7 a J . — B a c k w a t e r s of tlie I r r a w a d d y at B h a m o (No. 2 1 5 0 2 ).
G e n u s : Cylindrocystis Menegh.
2 8 . CYLINDROCTSTIS BREBISSONII M e n e g h . , 1 8 3 8 ; W . & G. S. West, B r i t , D e s m.
1 9 0 4 , p. 58, t. 4, f. 2 3 - 3 2.
Peniim Brcbissonii Ralfs, 1848.
Ilah.—Li the K a n - g y i at M u d o n ( No. 2 4 5 0 5 ).
2 9 . CYLINDROCYSTIS PYRAMIDATA W . & G. S. W e s t , F r e s h w . Alg. C e y l o n , 1902,
p. 134, t. 18, f. 1, 2.
F o r m a v a r i a b i l i s , c e l l u l i s d i a m e t r o u s q u e a d d u p l o l o u g i o r i b u s . Z y g o s p o r a o b l o n g o -
e l l i p s o i d e a , g l a b r a.
L o n g . 3 6 - 4 9 ^ ; lat. 2 2 - 2 6 / 4 ; lat. c o n s t r i c t . 2 1 ' 5 - 2 5 / i ; long, zygoap. 42/^; lat.
z y g o s p . 31//,; ( P I . x i i i , figs. 3, 4).
¡ J a l ) , — S p r i n g on t h e r i v e r b a n k at B h a m o (No. 2 1 5 0 1 ).
3 0 . CYLIKDROCYSTIS SUBPYBAMIDATA W. & G. S. W e s t , F r e s h w . i C i i l o r o n h y . Koh
C h a n g , 19Ù1, p. 162, t. 2, f. 8 - 1 1.
L o n g . 27^^; l a t . c o n s t r i c t . 15'5m.
H a h . — I n the K a n - g y i at M u d o n (No. 2 4 5 0 5 ).