20 
126. 
127. 
128. 
129. 
130. 
131. 
140. 
141. 
142, 
143. 
Cac 
Q 
Caen 
Tiel 
q 
62 
C. 
C. 
Q 
C: 
. depressum (Nag. », Lund. (C, Scenedesmus, Delp.) O.—Hoy. S.— 
TRANSACTIONS AND PROCEEDINGS OF THE [ Sess. LXIX. 
distinctis, scrobiculis centralibus nullis, granulis intra margines 
numerosioribus. 
Long. 37°5u ; lat. 31-5y ; lat. isthm. 75y ; crass. 20u. 
0.—Pond near Kirkwall. 
sphalerostichum, Nordst. S.—Lerwick ; Scalloway. 
Bressay, in pools, and also in plankton of Loch Beosetter ; Neugles 
Water. Plankton of Loch Asta. 
. bioculatum, Bréb. S.—Neugles Water ; Lerwick. Plankton of 
Loch Asta and of Loch Beosetter, Bressay. 
. tinctum, Ralfs. O.—Kirkwall; Hoy. S.—Le1wick ; Scalloway ; 
Bressay. 
. contractum, Kirchn., var. ellipsoidewm (Elfv.), W. and G.S. West. 
S.—Plankton of Loch Beosetter, Bressay. 
'. subcontractum, sp. n. (fig. 21). 
C. parvum, paullo longius quam latum, profundissime con- 
strictum, sinu angusto prope apicem, sed late aperto extrorsum ; 
semicellulz obverse semicirculares, apicibus latissimis et subrectis, 
angulis superioribus rotundatis; a latere vise subglobose ; a 
vertice vise subanguste elliptice ; membrana punctata ; pyren- 
oidibus singulis. 
Long. 33u ; lat. 30-31u ; lat. isthm. 6°5y ; crass. 16,. 
S.—Bressay, In pools, not uncommon. 
In outline this species much resembles C. stawrastroides, Eichler 
and Gutw. (in “ Rospraw. Wydz. matem.-przyr. Akad. Umiej. 
Krakow,” xxviil., 1894, p. 171, t. 5, £. 30), but is distinguished by 
its much larger size, its narrower isthmus, and the narrowly 
elliptical vertical view. Moreover, the apices of the semi-cells are 
never retuse, and the cell-wall is distinctly punctate. 
It should also be compared with C. aversum, W. and G. S. 
West. 
C. Hammeri, Reinsch [inclus. C. homalodermum, Nordst]. O.— 
Hoy. S.—wNear Scalloway. 
. galerittum, Nordst. S.—Lerwick. 
premorsum, Bréb, O.—Hoy. S.—Near Scalloway ; Loch 
Brindister; Bressay. 
. Corbula, Bréb. O.—Kirkwall. 
. Turpin, Bréb. S.—Plankton of Loch Asta. 
subpunctulatum, Nordst. OW—Kirkwall; Stromness. S.— 
Neugles Water. Plankton of Loch Asta. 
. punctulatum, Bréb. O.—Kirkwall; Stromness; Hoy. S.— 
Bressay, in pools, and also in the plankton of Loch Beosetter. 
. humile (Gay), Nordst. O.—Pond near Kirkwall. Plankton of 
Loch Kirbister. S.—Plankton of Loch Asta, and of Loch 
Beosetter, Bressay. 
Var. substriatum (Nordst.), Schmidle. O.—Stromness ; Fins- 
town; Hoy. S.—Lerwick; Neugles Water; Loch Brindister ; 
Bressay. 
Blyttti, Wille. O.—Kirkwall. 
Boeckti, Wille. OW Kirkwall; Finstown. SS. — Lerwick; 
Neugles Water. Plankton of Loch Asta, and of Loch Beosetter, 
Bressay. 
. subprotumidum, Nordst. S.—Lerwick. Plankton of Loch 
Brindister. 
. caleareum, Wittr. Long. 28-30u; lat. 25°5-27-5u; lat. isthm. 
7-724; crass. 15°5-16y. S.—Lerwick. 
This Desmid occurred abundantly in a small pond. 
