MasxELL.-—On the New Zealand Desmidies. 957 
visible in any ease, beyond, that is, the folds due to the bursting of the 
eell-wall, which were easily recognizable. - Consequently, I could only infer 
that the fronds had undergone self-division previous to conjugation ; and on 
this supposition those in which the inequality was but slight would have 
simply missed conjugation and were growing in the ordinary way. This 
being the case, if I am right, it results that each pair of segments in C. 
acerosum produces a zygospore, and therefore each whole frond produees 
two zygospores; but the process differs from that of C. selenewm and C. 
ehrenbergii in this, that the fronds do not shut themselves up in pairs in 
mueus, but are all enveloped in the same envelope. 
Certainly, I cannot say that I saw any fronds dividing, for the process 
had already begun, and was in full swing when first seen. But I am unable 
to aecount in any other way for the curious inequality of the arms. 
As C. acerosum has only a suture at the middle, and no secondary sutures, 
the bursting of the cell-wall anywhere but at the middle cannot be explained 
as in C. intermedium. Penium margaritaceum and other plants also open un- 
equally, but they too have secondary sutures. 
Closterium lineatum, Ehrenberg. : 
This is another of the plants observed conjugating. There is nothing to 
distinguish it from the English species. 
` Closterium diane, Ehrenberg. 
Also observed conjugating. 
I add a figure (20) of Scenedesmus quadricauda, to show the three bristles 
sometimes observable. | 
Also two figures, 21 and 22, as specimens of the curious monstrosities 
of growth often seen amongst Desmidiem, a family generally of such re- 
markable symmetry of form. Fig. 21 is Tetrachastrum (Holocystis) incisum ; 
fig. 22 is Docidium clavatum. 
Noman List or DESMIDIE REPORTED FROM New ZEALAND UP TO 1882. 
Ax asterisk in this list marks the species described by me as new in the foregoing and my — 
previous paper (vol."xiii., 1880, p. 297); a dagger marks those described as mew by Dr. 
Spencer in his paper (vol. xiv., pp. 295, 296) ; and a double dagger those reported by 
Dr. Spencer in the same paper, but not new. 
ore.—I include also Docidium (Pleurotenium) ovatum, of which I find the following 
notice in one of Professor Nordstedt's papers—'' Hee species quoque in Brasilid et Nova 
Zealandiá lecta est ;" but I do not know the plant.) 
Hyalotheca dissiliens. Spherozosma excavatum. 
dubia.tt ifo ; 
Aptogonum undulatum.* pulehrum.f f 
Desmidium aptogonium. vertebratum. 
8 i Micrasterias ampullacea." 
17 
