52 MESSES. W. AVEST AND G. S. WEST ON 



It differs from Euastrum rostratum^ E.alfs, var. frcemorsum, Nordst. (Fresliw. Alg. 

 of New Zeal. & Austr. p. 34, pi. iii. fig. 7), in the median projection not being truncate, 

 in the absence of the scrobiculse, in being more denticulate, as well as in the distinct 

 median papilla of the lateral view ; the poles of the vertical view are also rounded 

 and not truncate. 



Yar. ORNATUM, nov. var. (PI. VI. fig. 17.) Yar. lobo polari paullo longiore et incisura 

 mediana prof undiore et angustiore ; membrana granulis irregulariter ornata. 

 Long. 54 ^i ; lat. 33 ^t ; lat. lob. pol. 16-17 /u ; lat. isthm. 11 ^. 

 No. 0. 



48. Euastrum subeostratum, nov. sp. (PI. YI. fig. 6.) E. subparvum, circiter l^-plo 



longius quaro. latum, profunde constrictum, sinu lineari ; semicellulse trilobse ; lobis 

 lateralibus rotundatis, granulis acutis paucis 3 in ambitu et 3-1 intra marginem ; 

 lobo polari latissimo rectangulari, angulis supeiioribus subrostratis, apicibus 

 subrectis incisura mediana profunda aperta, granulis binis intra marginem lateralem 

 utrobique ; in centro tumore parvo ; a vertice visse oblongae, polls rotundatis granulis 

 acutis ornatis, in medio utrobique verruca magna emarginata instructse. 



Long. 38'5 ,u; lat. 32*5 ^.i \ lat. lob. pol. 20 ^ ; lat. isthm. 9 /i ; crass. 19 yu. 



No. 0. 



49. EuASTRTJM ELEGANS, Kiitz. Phycolog. Germ. p. 135 ; Palfs, Brit. Desm. p. 89, 



tab. xiv. fig. 7. {Cosmarium elegans, Breb. in Menegh. Synop. Desm. p. 222.) 



Yar. MADAGASCARiENSE, nov. var. (PL YI. fig. 18.) Yar. semicellulis in partibus 

 superioribus latioribus, apicibus multo convexioribus, in centro triangulo granulorurn 

 3 ; a vertice et a latere visse projectione mediana prominente truncata. 



Long. 29-37 ^; lat. 19-21 a« ; lat. isthm. 4-5-6 m ; crass. 15 /u. 



Nos. and 1. 



50. Euastrum personatum, nov. sp. (PI. YI. fig. 19.) E. submediocre, paene IJ-plo 



longius quam latum, in medio profundissime constrictum, sinu angusto-lineari 

 extremo ampliato ; semicellulae subpyramidato-truncatse, subtrilobae, incisuris late- 

 ralibus apertis obtusisque ; lobis lateralibus retusis, angulis inferioribus rotundatis, 

 angulis superioribus minoribus submamillatis ; lobo polari late rectangulari, late- 

 ralibus rotundo-convexis, angulis superioribus in spinam brevem validam productis, 

 apice incisura mediana alta angusta ; semicellulai supra isthmum tumore, in medio 

 scrobiculis binis horizontaliter ordinatis, intra angulos inferiores granulis tribus et 

 intra angulos superiores granulo singulo prteditcE, intra latera lobi polaris cum 

 papilla ; a vertice visse elliptica?, tumore mediano ; a latere visae ovatge, tumore 

 prope basin utrobique, papilla apicem versus utrobique, apice apiculatis. 



