212 



FRESH-WATER ALG^l FROM BURMA 



The spines of th 



present ou Turner's Indian specimens, but the 



forms 



from Ceylon, which were typical as regards general outline, likewise possessed longer 

 than the Indian forms (viae PI. xv, fig. 8). 





122. Arthrodesmus fusiformis sp. n. (PI. xv, fig. 4). 



A. magnus, pame lj-plo latius quam longus (sine spinis), profundissime con- 

 strictus, sinu aperto acutangulo ; semicellulse elliptico-fusiformes, ventre plerumque 

 convexiori quam dorso, angulis lateralibus subacutis spinam sublongam rectam vel 

 curvatum ferentibus, spinis subhorizontaliter dispositis vel leviter divergentibus ; a 

 vertice visae fusiforme^, polis acutis spinatis. Membrana glabra. 



Long. 44-46*5/*; lat. sine spin. 57*5-65/*, cum spin. 78-90/*; lat. isthm. 9*5/*; 

 crass. 20-2 1/*. 



Hab. — Mansang, near Hsipaw (No. 24193). 



Including the spines this species is about twice as broad as long. The cell-wall is rather thin, 

 and as far as could be judged is quite smooth. It stands very near to A. leptodermus Liitkem., 

 but is considerably larger, with longer spines, and a more fusiform vertical view. The under side 

 of the semicells is also more convex than the upper side, and the spines are slightly divergent. 



123. Arthrodesmus leptodermus Liitkem. Desm. Central China, 1900, p. 120, 



t. 6, f. 17-19. 



Forma semicellulis a fronte et a vertice visis ad polos minus attenuatis, sinu 

 ad extremum leviter angustiori. 



Long. 38*5/*; lat. sine spin. 38*5-42^, cum spin. 46-50/*; lat. isthm. 

 8-9*5/*; crass. 20/*. (PI. xv, figs. 5, 6). 



Hob. — Mansang, near Hsipaw (No. 24193). 



The Arthrodesmus figured by Wolle in his 'Desmids U. S.' 1£84, pi. 23, fig. 22, 23, as a 

 y of A. convergent with short aculei, is perhaps the nearest in general form to the Burmese 





vane 



but the spines are a little longer. A. minor Turn. (Freshw. Alg. E 



t. 11, f. 29) is possibly a small and rather more inflated form of the same plant. 



Another closely allied species is A. hiatus Turn. (1. c. p. 134, t. 11, f. 34, ,40; t. 82. f. 1), 

 which only differs in the more convex dorsal part of the semicells and the incurved spines. 



124. Arthrodesmus mucronulatus Nordst. Desm. Brasil. 1870, p. 232, t. 4, 



f. 58. 





Forma minor, apicibus semicellularum paullo depressis. 



Long. 16/*; lat. sine spin. 21/*, cum spin. 26*5/*; lat. isthm. 6 



Hab. — Mansang, near Hsipaw (No. 24193). 



Genus: Staurastrum Meyen. 



125. Staurastrum apiculatum Br<£b. Liste Desm. 1856, p. 142, t. 1, f. 23 



Long, cum apic. 19-5/*; lat. 19'5/*; lat. isthm. 7 



/*, mi. isinm. ifi 



Bab.— Mansang, near Hsipaw (No. 24193) 





♦ 



