BY G. I. PLAYFAIR. 317 



Genus Spirogyra Link. 

 Spirogyra crassa Kiitz. 

 Cell. veg. diam. 160-180, alt. plerumque 120-190, interdura 50; 

 meinbr. crass. 2 /x. 

 Lismore (249). 



Six, narrow, smooth chloroplasts making one turn each. Pyre- 

 noids very numerous, large for the size of the chloroplast, taking 

 up the full breadth or a little more. 



Spirogyra Grkvilleana var. australis, n.var. (PI. xlii., f.2.) 



Forma zygosporis ellipticis acuminatis, pra3 longitudine valde 

 latioribus. 



Cell. veg. diam 30, alt. 160-230. Zygo. long. 75, lat. 50 /x. 



Lismore (248). 



Cf. Sp. GrevLlleana{l{siSs.) Kiitz. in Petit, Spir. d. Paris, p. 10 

 PI. ii., f.1-6, (fig. 6 has pointed zygospores); also Borge, Zygne- 

 males, in Pascher, Siissw. Fl. Deutschl., p. 17, f.4. The chloro- 

 plasts of the vegetative cells are sometimes single, making 5 to 7 

 turns, sometimes double, making only 2 J turns, the edges scal- 

 loped, and pyrenoids very small. Ends of cell reflexed. The 

 zygospores are elliptic with pointed ends, not oval, and much 

 broader in proportion than in the type. Sporangial cells very 

 much swollen. 



DESMIDIACE^. 

 Genus Gonatozygon DeBary. 



GONATOZYGON MONOT^ENIUM DcBy. 



Long. 101-144, lat. centr. 11-12, ap. 12 /x. 

 Lismore (223, 254, 260). 



Var. TENUE, n.var. (PI. xli., f 1.) 



Cellulse quam forma typica angustiores; apicibus baud expansis 

 in cellulis liberis arcuatis nee planis. 



Long. 80-150, lat. centr. 8, ap. 8 /x. 



Lismore (223). 



The dimensions agree with the lowest of those given by W. & 

 G. S. West, Monog. i., p. 30, but the shape of the cells is unusual, 

 the diameter the same from centre to apices, the extreme ends 



