• 



222 



FRESH-WATER ALOM FROM BURMA. 



Of 



The figure given by Reinsch of St. Sebaldi is a very poor one, the front and vertical views 

 _ which do not correspond. The vertical view appears to us to be the more accurate. In addition 

 to the row of emarginate warts aloog the three sides of the apex of St. Sebaldi, there is also a 

 row of stout spines below them, which are somewhat variable in size and character. 



Another species oloseiy allied to St. Sebaldi is St. Manfeldtii Delp. (Desm. Subalp. 1877, p. 64 



f. 8-10: W. & G. S W 



t. 1, f. 29; Alg. Orkneys and Shet- 



land 



ab 



The specimens observed from Burma were smaller than Reinsoh's original examples, and the 

 margins of the basal part of the semicells were undulate, but in other respects they agreed with 

 -what we have always regarded as St. Sebaldi Reinsch. 



157. Staurastrum zonatum Borgesen, Desm. Brasil, 1880, p. 46, t. 5, f. 48. 



Var. prodi;ctum var. n. (PI xvi, fig. 14). 



Var. processibus duplo longioribus, apicibus semicellularum minus elevatis 

 (subtruncatis) et glabris. 



Long, sine proc. 30-31/*, cum proc. 44-46/i ; lat. sine proc. 15-5-17/*, cum 

 proc. 52-"»6/»; lat. isthm. 11^. 



JIab. — In the Kan-gyi at Mudon (No. 24505.) 



In this variety the processes of one semicell alternate with those of the other. The length 

 of the processes is considerably greater than in any other forms of St. zonatum. 



158. Staurastrum limneticum Schmidle. Ost-Africa Desm. 1898, p. 52, t. 4, f. 5. 



Var. Burmense var. n. (PI. xvi, fig. 13). 



St. mediocre, cireiter l|-plo latius quana longum cum processibus, profunda con- 

 strictum, sinu valde aperto apiculato ad apicera ; semicellulse late cuneatae, apice valde 

 clevato et subtruncato, angulis in processus longos denticulatos (processus unusquisque 

 annulis tribus vel quattuor denticulorum praeditis) regulariter et sursum curvatos pro- 

 duces, apicibus processuum conspicue trispinatis; a vertice visae 5-radiatae, corpore 



parvo, angulis in processus longos trispinatoa productis ; processibus alterius semicellulae 

 cum iis alterius alter nantibus. 



Long, sine proc. 31-32/*, cum proc. 54-58 /* ; lat. sine proc. circ. 17/*, cum proc. 

 77-92 fi ; lat. isthm. 7'5-8'5 p. 



Rah.— In the Kan-gyi at Mudon (No. 24505). 



Joshua (Burmese Desm. 1886, p. 643, t. 24, f. 1, 2) describes a species from Burma under 

 the name of St. platycerum, the vertical view of which resembles that of St. limneticum var. Burmense, 

 but the processes are stouter and the body rather larger. Joshua's description and figures are very 

 •erfect, and if his fig. 1 on pi. 24 represents the fiont view of St. platycerum it is very much 

 of a caricature. St. limneticum var. Burmense occurred abundantly, and its elegance of aspect, the 



lm 



f. 



of the semicells with their elevated apices, 



distinguish it from St. platycerum. 



curvature 



St. limneticum var. Burmense also resembles St. stellinum, Turn. (Freshw. Alg. E. India, 1893, 



p. 119, t. 15. f. 6), but the form of the semicells is quite different, and the processes are gracefully 



and upwardly curved. Moreover, the processes are furnished with three or four rings of conspicuous 

 denticulations, and are not irregularly and minutely undulate as in St. stellinum Turn., nor are the 

 peculiar marks present at the base of the semicells of the latter species found in St. limneticum 



Tar. Burmense, 



