124 



OOCYSTIS AND EREMOSPHiERA, 



ble, occasionally with a pyrenoid apiece. This form is very close 

 to O. crassa Wittrock, as figured by Osteiifeld, Proc. R. 8oc. 

 Edin., 1904-5, p. 1113, PI. i., f.<^, q.v. Var. ausfralica and var. 

 maximd, which are practically one, differ somewhat in shape 

 from the type, being more oval (broader in comparison with the 

 length) and with less pointed ends. 



OocYSTis CRASSA Wittrock. (Text-fig. 1 3ffl). 



In Wittrock at Nordstedt, Alg. dulc. exsicc. No.355; Bot. 

 Notiser, ISSO, p. 11 7. C/. G. S. West, Brit. Frw. Alga^, p. 227, 

 f.97C,D. 



Text-fig. 13. — (a)Ooci/8tis crassa Wittrock, ( x485); after C4. S. West. 

 (6) Var. Osten/eldii mihi; after Ostenfeld. 



Syn., O. Marssonii Lemm., Bot. Centralblatt, 1898, p. 151; 

 Ploner Forsch., 7, 1894, p. 24, T. i., f. 15-1 9. I have not met with 

 any form that I could identify with O. crassa. It is referred to 

 by G. S. West as a distinctly plankton-species. In W. & G. S. 

 West, Frw. Alg. N. Ireland, p. 6 8, the dimensions are given as 

 long. 18-3-24, lat. 13-15-5/i.. Chodat, I.e., p.l90, records long. 

 14-23, lat. 10-18/x for Swiss specimens. The ratio of length to 

 breadth in this species seems to be 1"3 to 1'4:1"0. 



Var. OsTENFELDii, nom.nov. (PL vii., f.l8, 19). 



Cellulse lateribus sequaliter arcuatis, in medio baud subangu- 

 latis; apicibus acuminatis baud incrassatis. Chloroplastides 2-4, 

 interdum pyrenoidibus singulis instructte. 



Cell. long. 16, lat. 11/x. 



Lismore, river (274, 281). 



