SOME XOETH AMERICAN DESMIDIE.E. 265 



147. Staurastrum aspinosum, Wolle, Desm. II.S. p. Ii3, pi. 51. figs. 22, 23. 



Var. AXNULOSLM, nov. var. (PL XVII. fig. 10.) Var. spinis brevibus multis circa 

 basin processuum, processibus undulato-denticulatis, cum annulo spinariim majorum 

 parti tertice loEgitudinis processus uniuscuj usque de apice. 



Long. s. proc. 17 /i, c. proc. 46 n ; lat. s. proc. circ. 17 ^j, c. proc. 52 ^ ; lat. isthm. 5-8 n. 



We have only seen one example of tliis Aariety. 



148. S. BARBATUM, noT. sp, (PI. XVII. fig. 11.) S. parvum, 1^-plo longius quam 

 latius (sine processibus), modice constrictum ; semicellula? obsemicirculares, 

 dente parvo utrobique basin versus constrictionis, apicibus subconvexis, angulis in 

 processus longos acute trinodulosos productis, apicibus subcapitatis cum spinis 

 brevibus divergentibus armatis; a vcrtice visas triangulares, lateribus levissime 

 concavis, angulis in processus longos acute 1-nodulosos productis. 



Long. s. proc. 16 /n, c. proc. 38'5 ft; lat. s. proc. 12^, c. proc. 38-40 fi; lat. isthm. y /i. 



This differs from S!. aspinosum , Wolle, in its smaller size and shorter arms, which are 

 regularly 3-4-nodulose and not furnished with irregular 23erpendicular spines ; the apices 

 of the processes are also very different. 



149. S. BRACiiiopROMiNENS, Boerg. in Vidensk. Meddel. 1890 (1891), p. 47, t. 5. fig. 52. 

 Long. s. proc. 29 ,u, c. proc. 46 /u ; lat. s. proc. 19 /x, c. proc. 60 ^i ; lat. istbm. 105 ^t ; 



crass. VI IX. 



As Poergesen states tliat he was somewhat uncertain as to the vertical view, we give 

 a figure. (PI. XVII. fig. 12.) 



Var. ROBUSTUM, nov. var. (PI. XVII. fig. 13.) Var. processibus minus divergentibus 

 et validioribus, verrucis ad apices majoribus, etiam cum verrucis longis minoribus 

 emarginatis prope basin marginis superioris ; membrana non ornata. 



Long. 27-30 m ; lat. c. proc. 545-60 ^u ; lat. istbm. 6-7 a^. 



150. S. XATATOR, West, in Journ. Linn. Soc. (Bot.) xxix. (1892) p. 183, pi. 23. fig. 14. 

 Var. CRASSUM, nov. var. (PI. XVII. fig. 4.) Var. semicellulis projectione eentrali 



multo majore, annulo grauulorum (circ. 12), granulis tribus intra annulum ; verrucis 

 ad apicem truncato-denticulatis. 

 Long. s. proc. 31-36 a«, c. proc. 41-48 ^t ; lat. s. proc. circ. 19 ^i, c. proc. 65-69 /* ; lat. 

 isthm. 7'5-9"5 ^.i ; crass. 25 ^n. 



The vertical and lateral views of this species remind one of S. mimiecfpoUense, Wolle, 

 but the front view at once precludes this idea. 



151. S. GRALLATORIUM, Xordst. in Vidensk. Meddel. 1869 (1870), p. 228, t. 4. fig. 52. 

 Var. AMERICANUM, nov. var. (PI. XVII. fig. 15.) Var. cellulis profundiiis constrietis, 



semicellulis latioribus quam in formfi typica (obverse semicircularibus), apicibus 

 truncato-convexis et glabris, processibus divergentibus sed incurvatis. 

 Long. s. proc. 29-31 /i ; lat. s. proc. 21-23 ^, c. proc. 73-75 m; lat. isthm. 6-5-7-5 /* ; 

 crass. 16 ^. • - 



