50 DR. G. S. WEST ON THE ALGÆ OF 
Order CONJUGATÆ. 
Family ZYGNEMACEÆ. 
Genus MOUGEOTIA, 47. 
7. MoUGEOTIA SUBCRASSA, sp. п. (Pl. 2. figs. 4-5.) 
M. crassa, cellulis vegetativis diametro 6—61-plo longioribus, chromato- 
phora magna et crassa cum pyrenoidibus subirregulariter dispositis numerosis 
(15-24); sporis ubi conjugatione scalariformi productis, globosis et sub- 
parvis, diametro cellularum veget. æqualibus ; membrana spore glabra et 
indistincte lamellosa ; cellulis conjugationibus fere rectis vel levissime 
curvatis. 
Crass. cell. veg. 41:5-43 ш ; diam. spor. 40-41 y. 
Hab. Yan Yean Reservoir ; among the weeds (Oct. and Nov. 1905). 
The best conjugated specimens of this species were observed in November. 
It is remarkable for the relatively small size of the spores as compared with 
the diameter of the vegetative cells, a character which distinguishes it from 
M. scalaris, Hass., and M. crassa, Wolle. It is also distinguished from the 
former by the much greater thickness of its vegetative cells and by the larger 
chloroplasts with more numerous pyrenoids; and from the latter by its 
slightly longer and thinner vegetative cells. 
The spore-wall is thicker next the sterile cells than at its exposed parts, as 
in these regions the partition-walls which eut off the fertile cell (spore) from 
the two sterile cells are fused with the more newly-formed wall of the spore. 
It was this manifest partition of the conjugated structure into fertile and 
sterile cells, before the formation of any actual spore-walls, which induced 
Wittrock to regard this part of the life-history of Mougeotia as a rudimentary 
sporophyte. 
8. MOUGEOTIA RECURVA, (Назз.) De Toni.—Mesocarpus recurvus, Hass. 
Brit. Freshw. Alg. 1845, t. 43. fig. 2. 
Crass. cell. veget. 12-14 ш; diam. spor. 25-28 p. 
Hab. Yan Yean Reservoir ; among weeds (Nov. 1905). 
Lam in considerable doubt about this determination. Only a few speci- 
mens were observed, and they differed in the proportionately longer vegetative 
cells and in the straightness of the conjugating cells. The plants observed 
were probably abnormal states, as some of the filaments had produced both 
globular and cylindrical aplanospores, the former (diam. 24 ш) at the outer 
angles of geniculate cells (vide Wittrock, in Bih. till Sv. Vet.-Akad. Handl. 
i. (1872) t. 2. figs. 7, 8), and the latter (long. 34 u ; lat. 14 ш) in the middle 
of straight cells. 
