14 
36. 
37. 
38. 
39. 
40. 
41, 
52: 
TRANSACTIONS AND PROCEEDINGS OF THE [Sess. LXIX. 
Many species of Loth Ziygnema and Spirogyra were observed in 
the sterile condition or in such a condition as precluded their 
accurate identification. Representatives of both genera occurred 
in quantity in the plankton, 
Family Dresmmi1acez. “ 
Genus GONATOZYGON, De Bary. 
G. monotenium, De Bary. (G. Ralfsii, De Bary). 0.—Pond near 
Kirkwall. S.—Bressay, in a ditch ; ? platen! of Loch Asta and 
of Loch Beosetter, Bressay. 
G. Brebissonu, De Bary. 0.—Finstown. S. —Bréssay. 
Var. leve (Hilse), W. and G. S. West. O.—Hoy. 
. Kinahani (Arch.), Rabenh.  S.—In ditches, and in plankton of 
Loch Beosetter, Bressay ; plankton of Loch Asta and Neugles 
Water. 
2 
Genus GENICULARIA, De Bary. 
G. Spirotenia, De Bary. Diam. cell. 20-22; long: = 250-307 u' 
_(fig. 17). _S—Plankton of Loch Beosetter, Bressay-” 
The specimens of this rare Desmid were quite typital; and cells 
possessed either two or three spiral, parietal chloroplasts. 
Genus MESOTZNIUM, Nag. 
M. De Greyi, Turn., forma major, W. and G.S. West. Long. 100z ; 
lat. 264. O.—W. of Kirkwall. 
M. chlamydosporum, De Bary. O.—Ward Hill, Hoy. S.—Bressay’; 
near Lerwick. 
. M. Endlicherianum, Nag. O.—W. of Kirkwall. 
Var. grande, Nordst. O.—W. of Kirkwall. S.—Scalloway. 
Genus CYLINDROCYSTIS, Menegh. iw te It 
. CO. Brébissonn, Menegh. 0.—Kirkwall; Hoy. S.—Lerwick . 
Bressay. 
. C. crassa, De Bary. O.—Finstown; Kirkwall; Stromness; Hoy. 
S.—Lerwick ; Neugles Water. 
CG. diplospora, Lund. O.—Hoy. 
Genus NETRIUM (Nag), W. and G. S. West. 
. N, Digitus (Ehrenb.), Itzigsh. and Rothe. 0.—Kirkwall; Hoy. 
S.—Scalloway ; Lerwick; Neugles Water; plankton of Loch 
Beosetter, Bressay. 
. N. interruptum (Breb.), Liittkem. S.—Neugles Water. 
. N. oblongum (De Bary), Liitkem. O.—Kirkwall. 
Var. cylindricum, W. and G. S. West. -0.—W. of Kirkwall. 
Genus PENIUM, Bréb. 
. P. Navicula, Bréb. S.—Lerwick ; Neugles Water. 
. P. Mooreanum, Arch. S.—Scalloway. 
 P. minutissimum; Nordst. O.—W. oi Kirkwall; Hoy. S. 5 eek 
P. margaritaceum (Ehrenb.), Bréb. |S. —Bressay._ eS a 
Var. trregularins, var. n. (fig. 23). 
“Var. major, granulis majoribus et irregulariter dispositis: “iyide. 
254u ; lat. max. 29u ; lat. apic. 20u. 
