Maskell. — On New Zealand Desmidiese. 29 



'■' Docidium ovatuvi, Nordstedt. 



In my paper of 1880 I reported this species under the 

 name of D. dilatatiun. I had not then seen Professor 

 Nordstedt's Brazihan plant, identical with it. But a clerical 

 error crept into my description of it, as the length was given 

 as aVhi. : this should have been ^in. The dimensions are, in 

 point of fact, somewhat variable. Long., 340-380 /a; lat., 

 85-96 /x. 



Mr. Turner thinks that our New Zealand plant differs a 

 little from the Brazilian, and in several specimens I can 

 observe differences in the granules at the ends ; but probably 

 these distinctions are not important. 



Docidium ovatum, Nordstedt, var. tumidwn, var. nov. 

 Plate VI., fig. 54. 



Frond large, stout, tumid-cylindrical ; constriction rather 

 wide and deep; segments regularly ovate, with smooth edges, 

 and tapering without dilatation to the soniewhat wide ends, 

 which bear conspicuous small tubercles, the tubercles not 

 set close together. Cytioderm punctate. 



Long., 250 fx; lat. max., 11'2/a; lat. constric, 58//.; lat. 

 term., 27 /x. 



Eutherford's Swamp, Otaki. 



A form clearly distinguishable from the last, being much 

 shorter and proportionately broader ; and the tubercles at the 

 ends are more conspicuous and wider apart. 



Genus Closterium, Nitzsch. 

 Clostcriuvi diance, Ehrenberg, var. arcuatum, Breb. 

 Plate VI., fig. 55. 



The dimensions of this plant vary considerably. The 

 largest specimens I have seen reach as much as 530 jj. (chord 

 of arc) ; the smallest are no more than 175 fi. In the largest 

 the ends are slightly emarginate, as shown in fig. 55b, and 

 faint transverse striae can be made out in the middle (fig. 55c). 

 I think the more semicircular, or genuine, form of C. diance 

 does not occur here. 



'" C. vemis, Kiitzing. Plate VI., fig. 56. 



This is also variable in size, ranging from 114 /x. in length 

 down to 67 /A (chord of arc). I should take this to be only a 

 small form of C. diance, but there may be something in the 

 distinction made by Delponte (" Desm. Subalp.," pis. xvii. 

 and xviii.) that in C. diancz the ends are emarginate, in C. 

 vemis simply tapering. 



'•' C. cyntliia, de Notaris, /or7?za. Plate VI., fig. 57. 

 The strias are excessively faint, and the ends thicker than 

 in the type. The plant would approach very closel}' to 



