534 New and hare freshwater alg^ 



Genus T e t k a e d r o n Kiitz. 

 Tetraedron granulosum, 11. sp. (PI. Ivii., f.17, l>^). 



Cellulpe plaiise, parvse, triangulares; lateiibus rectis in medio 

 levissiineconNexis; angulis acutis haud iiitiatis; membrana grosse 

 g]-aiiulata, granulis in quincuncein ordinatis. A latere visa", 

 mudice cuinpressie, elliptico-lanceolata^, angulis acuminatis. 



Cell, diain. 21, crass. 11/x. Lismore (302): 



The specimens noted were Hat, not tetrahedral, triangular with 

 straight sides shghtly convex in the centre; angles acute, not 

 inflated; membrane coarsely granulate in (|uiiicunx. From the 

 side, elliptic-lanceolate with pointed ends. In the centre of the 

 cell might be discerned a minute nucleus enclosed in a pale brown 

 globule (?pyrenoid). ►Sometimes the nucleus was entirely hidden 

 Ijy the globule, which then had the appearance of a large brown 

 pyrenoid; cf. Oocyst is and Bremosj^hcera, p. 126, remarks on 0. 

 lacustris \. pahtdeiisis; and p. 137 on 0. oirdis y. cf/Zindracra, 

 where the same phenomenon occurs. 



Tetraedron (iUADRATUMf.3iiN0R Keinsch. (PI. Ivii., f.lD). 



Cellula plana; diau]. sine spiiiis 17/x. JJsmore. 



Forma excavata, n.f. (PI. Ivii., f.2()). 



Forma plana, lateribus alternantibus conca^ is, alteris levissime 

 convexis; angulis spinis brevibus acutis singulis armatis. 

 Cell, diani. 19, alt. Ib/i, s.sp. Lismore. Cum priori. 



Cf. Pveinsch, Monog. Folyedrimn, p.500, T. iv., fig.7r/. This is 

 a variant of f. inlnor with alternate sides conca\ e, the other sides 

 generally somewhat convex. , 



Tetraedkon caudatum v. australe, n.var. (PI. Ivii., f.21, 22). 



Celluky inaiqualiter pentaedricic; angulis acutis, spinulis min- 

 utis singulis armatis; lateribus coiicavis; utrinque infra marginem 

 angulis mainmillatis armatis singulis instructa;. A latere, plaiue 

 (ichnographia universa respecta), lanceolato-elliptica^ apicibus 

 acutis armatis; altero latere convexai, altero autem angulis main- 

 millatis armatis binis projicientibus, instructjv. 



Cell. lat. max. c. spinis 21/x. Lismore. Cum priori. 



