Freslmater Algse of North Wales. By Wm. West. 283 
*S. depressum (Breb.). (Spondylosium depressum Breb.). C., 
Do. 
Lat. 10 [X. 
S. pulchellum (Arch.). (^Spondylosium pulchelluin Arch.). S. 
Genus Onychonema Wallich. 
0. Nordstedtiana Turn. C. 
Genus Hyalotheca Ehrb. 
H. dissiliens (Sm.) Breb. Common. 
This was seen with zygospores from Capel Curig. 
Yar. minor Delp. C. 
H. mucosa Mert. P., Do. 
*jET. undulata Nord. C. 
Lat. 7'5-9/x; long. 13 -5-16 
Genus Gymnozijga Ehrb. 
G. moniliformis Ehrb. (Bamhusina Brebissonii Ktz.). A., S., 
Do., F., D. 
Genus Desmidium Ag. 
coarctatum Nord. var. cambkicum nov. var. Fig. 2. 
Yar. cellulis brevioribus et apicibus latioribus. 
Long. 22*5-27 p; kt. 42-45 fx; lat. isthmi 35- 
37 • 5 /X ; lat. apic. 17 * 5-20 ix ; crass. 35 /x. 
This chiefly differs from the type in the cells being shorter and 
having broader apices. C. 
This variety is somewhat doubtfully placed under this species, 
which it seems to connect with Desmidium cylindricum Grev., the 
shape of the cells in front view being nearer the latter, but the breadth 
of the apices bringing it nearer the former. The side view shows the 
apices to be only about half the thickness of the cells, corresponding 
in this respect with D. coarctatum Nord. (in ‘Freshwater Algae of 
New Zealand and Australia,’ p. 25, plate ii. fig. 3), with which it also 
agrees in having the constriction reduced to a mere retuseness in the 
side view. It differs from D. quadratum Nord. in the form of the 
cells in side view, as well as in the relative breadth of the apices in 
the same view, and it is well distant from D. graciliceps (Nord.) 
Lagerh. and D. majus Lagerh. in the different shape of its cells. 
D. laticeps Nord. has the same length of cells, but their breadth and 
thickness is almost twice as great, and the apical breadth is three 
and a half times as great. 
D. Stvartzii Kalfs. A., D. 
D. aptogonium Breb. Do., A., S., P. 
