THE FEESHWATER ALG^ OF MADAGASCAR, 49 



Genus Euastrum, Ehrenb. 

 39. Euastrum bellum, Nordst. Desm. Brasil. tcab. ii. fii,'. 6. 



Var. madagascariense, nov. var. (PL VI. fig. 7.) Var. minor ; semicellulfc a fronte 

 visas angulis inferioribus unidentatis, angulis superioribus dcntibus nonniillis intra 

 angulos additis, lobo polari truncate (non emarginato) dcntibus nonuullis intra 

 apicem additis, annulo granulorum 8 ad medium et granulis 3 in formam trianguli 

 utrobique appropinquatis; a vertice visae polis non capitatis, lobo polari subquadrato 

 lateribus subrectis. 

 Long. 54 ^ ; lat. ad bas. semicell. 33 /i ; lat. max. 44 ^l ; lat. lob. pol. 13 /u ; lat. isthm. 

 7'7 fjt; crass. 21 ^. 

 No. 0. 



40. Euastrum hypochondroides, nov. sp. (PL VI. fig. 8.) F. IJ-plo longius quam 

 latum, medio profundissime constrictum, sinu lineari extremo ampliato; semi- 

 cellulse trilobae, lobis lateralibus rotundo-ovatis margine superiore rotundatiore, 

 granulis acutis magnis irregulariter dispositis, lobo polari elongato-quadrato, apice 

 convexo-truncato granulis acutis irregulariter ordinatis, annulo granulorum 10 et 3 

 vel 4 intra annulum in medio sitorum ; semicellulse a vertice visae oblonga? utroque 

 polo subcapitato et granulato, medio utrobique tumore granulato praeditae, lobo 

 polari elliptico-rotundato granulato, a latere visae obcuneatae tumore basali, lateribus 

 subconcavis et apicibus convexo-truncatis praeditae. 

 Long. 49-52 fx ; lat. 37-41 fi; lat. lob. pol. 12*5-13-5 /x; lat. isthm. 9*5 /*; crass. 16 ^. 

 No. 1. 



The nearest species to this is K sphyroides, Nordst. (Freshw. Alg. of N. Zeal. & 

 Austr. p. 32, pi. iii. fig. 3), from which it differs in its larger size, its longer lobes with 

 more granules, which are larger and more acute and which also cover the whole of the 

 apical portion of the polar lobe. In the vertical view it differs in the subcapitate poles 

 and the rounded central inflation, and in the lateral view it is comparatively longer. It 

 differs from E. hypochondriim, Nordst. (De Alg. et Char. i. p. 8, t. xvi. fig. 11) m its 

 front view by its shorter lateral lobes with larger irregularly disposed granules, in its 

 subrectangular basal angles, and its longer and convex polar lobes. The vertical view 

 differs in having each pole subcapitate, and in the polar lobe being rounded-eUipticai 

 (not quadrate-oblong) with fewer and larger scattered granules. 



Var. irregularius, nov. var. (PI. VI. fig. 9.) Var. granulis acutioribus longioribusque 

 etiam plus irregulariter dispositis (3-4 associatis). 

 Long. 50 /u ; lat. 39 ix ; lat. lob. poL 135 ^ ; lat. isthm. 9-5 fx. 

 No. 0. 



41. Euastrum, n. sp. (PL VI. fig. 10.) E. semicellulis a vertice visis elliptico-fusi- 

 formibus, polis subacutis, spinis brevibus ornatis, in medio utrobique inflatione 



SECOND series. — BOTANY, VOL. V. ^ 



Mc.Bot. Garcii. 



