330 FRESHWATER ALG^ OF LISMORE DISTRICT, 



Cf. W. & G. S. West, Alg. fr. Burmah, PL 14, f.23, and Nord- 

 stedt, Desm. C. Braz., PI. 2, f.l56. Micr. tropica is a form of M. 

 Mahahuleshwarensis with a single lateral lobule. Raciborski's 

 three forms, Desm. Tapakoomasees, f.7, 15, 16, also belong to 

 that species. The forms with two lateral lobules are the direct 

 outgrowth of those with one, and those with three are developed 

 from those with two. The peculiar polar lobe with its apical 

 prolongations is characteristic, and every Micrasterias having 

 such belongs, biologically, to the same species. M, euastroides 

 Joshua, Burmese Desm., P1.22, f.l4, is another variant of M. 

 Mahahuleshwarensis^ and its P indivisa Nord., might, from the 

 point of view of its form alone, be placed under M. tropica. 

 Having regard, however, to the variability of all these forms, 

 and especially of M. Mahahuleshwarensis., it is perhaps better to 

 keep them as three distinct conventional types. 



M. Mahabuleshwarensis var. ampullacea (Maskell) Nord. 



Long. max. 174, centr. 142; lat. max. 154, lob. pol. 86, coll. 28, 

 isth. 22 /x. 



Lismore(187, 193). 



Micr. ampullacea Maskell, Trans. JSJ.Z. Inst., 13, PI. xi., f.6, 7, 

 differs only from M. Hermanniana Reinsch, Spec, generibusque, 

 PI. 2, f.B, in having the three lateral lobules thicker, shorter, and 

 more stumpy. A form with the third lateral lobule just started, 

 as figured by Hardy, Vict. Natural., 1905, f.3, is common in this 

 country, and is found here in the river along with the full- 

 grown form. 



Genus Xanthidium Ehr. 

 Xanthidium inchoatum Nord. f. (PI. xlii., f.9a.) 

 Long, semic. 18, lat. 32, isth. 8^. Spinis nullis. 

 Lismore (240). 



Cf. Nordstedt, Frw. Alg. N.Z., 1888, PI. 4, f. 30a, semicell. 

 superior. Synonyms of Xan. inchoatum are Ar. Incus Bulnh., 

 Desm. Sachs., Pl.ix., f.3; Ar. Incus forma a, Lund., Desm. Suec; 

 Ar. Bulnheimii Rac, Desm. Nowe, 1889, p. 23, T. ii., f.17; Ar. 

 Incus, "large form," Wolle, Desm.U.S, P1.24, f.l. 



