THE FRESHWATER PLANKTON OF THE SCOTTISH LOCHS. 499 
Long. 436; lat. 54°5 «; lat. apic., 16 u. 
Hab.—Loch Shiel, Inverness. 
The Scottish examples were proportionately shorter than fis described and figured 
by Gurwinski from Poland, but were otherwise similar. The apices of the cells are a 
little stouter than in typical Cl. turqidum. 
10. Cl. Kiitzingu, Bréb., var. onychosporum, var. n. (Pl. 6, fig. 22). 
Var. cum anegulis zygospore incrassatis et productis in ungues acutos quattuor, 
ungues prope partem dorsalem semicellule intra marginem. 
Lat. cell. 15-18; long. zygosp. sine ung. 43-46, cum. ung. 45-50 u; ae ZY ZOsp. 
sine ung. 324, cum ung. 40-43 4; long. ung. 5-6 m. 
Hab.—Loch Stranabhat, Lewis, Outer Hebrides. 
This variety is well characterised by its peculiar zygospore. 
11. Cl. setacewm, Ehrenb., var. elongatum, var. n. (Pl. 6, fig. 21). 
Var. cellulis elongatis et angustis, diametro 60—65-plo longioribus. 
Long. 740-780 »; lat..12—-12°5 u. 
Hab.—Loch an Sgath, Lewis, Outer Hebrides. 
This variety is chiefly remarkable for the great prolongation of the attenuated 
extremities. The cell-wall was colourless and the striolations scarcely discernible. 
Genus Micrasterias, Ag., 1827. 
12. M. Wallichi, Grun., “ Siissw. Diat. u. Desm. Ins. Banka,” Rabenh. Beatrdge z. 
Kennimss u. Verbreit. der Alg., H. 2, Leipzig, 1865, p. 14, t. 2, f. 21. 
Long. 181-190; lat. 152-160; lat. isthm. 30 x. 
Hab.—Loch Ruar, Sutherland (J. Murray)! 
This Desmid is a close relative of M. Mahabuleshwarensis, Hobson, but differs in 
the subdivision of the superior lateral lobes. It is a rare plant, and was previously 
unknown from the British Islands.* 
Genus Cosmarium, Corda, 1834. 
13. C. subcontractum, W. & G. 8. West. 
Hab.—Loch na Cloiche Sgoilt, Inverness. 
This species has only previously been observed from the Shetland Islands. 
”? 
14. C. moniliforme (Turp.), Ralfs, forma panduriformis, Heimerl, ‘‘Desm. Alp, 
Verhand. k. k. zool.-bot. Ges. Wien, 1891, p. 598, t. v., f. 11. 
Two forms of this were observed :— 
a. Cells small ; cell-wall distinctly punctate. Long. 21-22; lat. 11°5-13 u; lat, 
isthm. 7°5 « (Pl. 7, fig. 6). 
Hab.—Loch Bairness, Inverness. 
* Mr Murray has also collected this species from the following lochs:—Lochs Nan Eun and Bhaic, 
Perthshire ; Loch nan Cuinne, Sutherland ; Lochs Burraland and Littlester, Shetlands. It is entirely due 
to Mr Murray’s investigations that this species is known from the British Islands.| 
