THE FEESHWATER ALGJE OF MADAGASCAE. 79 



149. Statjeastrum pseudotetracerum, nob. (PL VIII. fig. 39.) {S. contorttim, Dclp., 

 var. pseudotetracerum, Nordst. Freshw. Alg. of New Zeal. & Austr p 37. tab iv' 

 %. 9.) 



Long, sine proc. 19-21^; long, cum proc. 23-2G^t; lat. cum proc. 24-26^; kt. 

 isthm. 7*5 /u. 

 No. 18. 



150. Staurastrum volans, nov. sp. (PI. IX. jBgs. 10-11.) S. parvum, duplo longius 

 quam latum (sine processibus), modice constrictum, sinu aperto et obtuso ; scmi- 

 cellulae cyatbiformes, apicibus valdc convexis, angulis supcrioribus in i)rocessus 

 divergentes curvatos (sursum) profundc 5-undulatos attenuates productis, apieibus 

 bifurcatis; a vertice visse globosae, processibus binis rectis undulatis attenuatis 

 instructae ; membrana glabra. 



Long. 18-19^; lat. sine proc. 9-5-10-5/I, cum proc. ti-18/x; lat. isthm. 3-8-4 fi ; 

 -crass. 8-95 yu. 

 Nos. 1 and 3. 



151. Staurastrum leptocladum, Nordst. Desm. Brasil. p. 218, tab. iv. fig. 57. 



Yar. CORNUTUM, Wille, Bidrag till Sydam. Algfl. p. 19, tab. i. fig. 39. 



Long. 31-83 /u; lat. cum proc. 59-82 /i ; lat. isthm. 4'5-7"5 ^< ; crass. 13-5 /x. (PL IX. 

 figs. 12-13.) 



Nos. 0, 1, 3, and 36. 



It is a curious fact that out of a large number of examples examined this variety only 

 occurred, not a single specimen of the type being seen. In examining a large number 

 of examples from the United States of America also, not one type specimen was met 

 with; W. B. Turner remarks the same thing with regard to the Indian specimens 

 {Freshw. Alg. of E. India, p. 123). 



152. Staurastrum aj^nulatum, nov. sp. (PL IX. fig. 7.) S. parvum, paullo latius 

 quam longum (cum processibus), modice constrictum ; semicellulse forma incudis 

 apice convexge spinis brevibus omatse, apicibus processuum triaculeolatis, in basi 

 inflatse seriebus horizontalibus duabus granulorum (granulis supcrioribus majoril)us) 

 praeditae ; a vertice visae triangulares, lateribus concavis a spinis circiter 11 ornatis, 

 intra marginem unumquemque serie spinorum, angulis in processus breves apicibus 

 triaculeolatos productis. 



Long, cum spin. 32o/u; lat. cum proc. 36/*; lat. isthm. 10'5 /*. 



No. 0. 



This differs from *S'. aculeatum, Menegh., var. ornatum, Nordst. (Desmid. Spetsb. p. 40, 

 tab. vii. fig. 27), in its smaller size, its longer processes, its fewer, shorter, and simple 

 spines, and in its basal inflation having two rings of granules ; the vertical view also has 

 a series of spines within each lateral margin. 



