188 



FRESH-WATER ALG/E FROM BURMA. 



24. Mo ug eot/ a parvula Hass., 1843. 



Mcsocarpus parvuhis Hass. Brit. Freshw. Alg. 1845, p. 169, t. 45, fio-s. 2-3- 



De Bary, Conj. 1858, p. 80, t. 2, f. 15. 



Var. ellipsoidea var. n. (PI. x, figs. 14, 15). 



Var. sporis transverse rhomboideo-ellipsoideis. 



Crass, cell veget. 9*6-1 1*5^; long. spor. 27-28/*; lat. spor. 21-23/*. 

 Hub.— Mansang near Hsipaw (No. 24193). 



25. Mougeotia producta sp. n. (PI. x, figs. 16-19). 



31. cellulis vegetativis diametro 12-20-plo longioribus; sporae quadrate, lateribus 

 concavis vel leviasime convexis, angulis productis et truncato-obtusis, saepe tortse cum 

 angulis duobus in planitic perpendiculariter disposita ad planitiem angulorum duorum 

 alteriorum ; aplanosporaj oblique doliformes apicibus productis truncato-obtusis: mem* 

 brana spor;e punctata, firma sed tenuiori ad angulos. 



Crass, cell, veget. 7-8/*; lat. spor. 29-37*5/*; long, aplanospor. 33-37/,, • 



lat. aplanospor, 17-18/t. 



J fab — In a ditch at the side of salt works, Vizagapatam (No. 17916). 



M. product a is characterized by its peculiar spores, which are quadrate in form with produced 

 angles. The angles are subtruncate, and the spore-wall, which is of the normal thickness everywhere 

 -Ise, is very thin at these points. This is the reverse of the usual condition in which the wall is 

 thickened at the angles. 



It 



to 3L 



vegetative oells, and in the produced, thin-icalled angles of the spores. 



(Kiitz.) Wittr., but differs from that species in its longer 



The 



were of special interest, because of the presence of aplanospores in no way 

 different from those which are found in the genus Gonatonema, These spores were formed from the 

 contents of one cell only, and were obliquely barrel-shaped with produced poles. The wall of the 

 aplanospore was of exactly the same character as that of the spore which results from conjugation, 



Not only were these asexual spores being 



'he truncate extremities of the angles be 



formed 



filaments not otherwise ooncerned in spore-formation, but they were 



in 



filaments which were also taking part in conjugation (PI. x, fig. 16). An aplanospospore could 

 frequently be observed next to a quadrate spore, which latter was the result of the conjugation of 

 the adjoining cell with a cell of another filament. Thus the characters of the two genera Mougeotia 

 and Gonatonema are here combined in the same species, and can be observed in different parts of 

 the same filament. 



TOttrook has described and figured aplanospores in Mougeotia cakarea («* Wittr. Gotl. 01. soly. 



tin' . n ; P ' H , ' ' gS ' ' '• Th ~ e 6p ° reS WCTe ° Ut 0ff from the *»0. «db V *e forma- 

 modoced Z 2 r S m - a T ner 6triC% TOmparable With the method ot f °™»tion of th. spore 



West Obs. on Con, 1*98, p. 38). The aplanospores ot Mougeotia prod,«ta may bo of this type, 



VentriLZ wL J ", § ► JZT*. mat6^ial • th<> Ep ° re9 mUch resembM those of Qona.oLa 

 tmtnconm W.ttr. and most probably orginated in a similar manner 



sole "TZZttLl^ ^l 1 " "' " U Sh ° W that alth0 ^ ^-pore-formation is ft. 

 inX stTes „f ; ril 7 ]Ugat r ; 8nd * ^ «JP" o' preformation are sW to erist 



genns MougeoUa ,„ w h.ch spore-formataon resulting from conjugation has ceased to osist. 



