Transactions of the Society. 
6 
Long. 90-92 y ; lat. 48-50 y; lat. isthm. 13 *5- 
15 fJL. 
Hah. Castletown, Co. Cork, Ireland. 
C. scoticum sp. n. Fig. 23. 
C. magnum, circiter diametro lj-plo longius, profunde 
constrictum, incisura sublineari angusta extremo ampliata ; 
semicellulae truncato-pyramidatae lateribus convexis, angulis 
inferioribus et superioribus rotundatis ; a vertice visae late 
ellipticae ; a latere visae subcirculares ; membrana granulata, 
granulis parvis subconcentrice margines versus ordinatis, 
medium versus dispersis ; pyrenoidibus binis. 
Long. 150 y ; lat. 105 y ; lat. isthm. 35 y. 
„ 130 y; „ 98 y; „ „ 46*5 y; crass. 
62*5 y. 
Hab. Ben Laoigb, Craig-an-Lochan, and Glas Maol, 
Scotland. 
It differs from C. Schubelerii Wille (Bidrag til Kunds. om Norges 
Ferskv. Alg., p. 34, t. ii. fig. 23) in its larger size, its more elongate 
cells of different form, its broader isthmus, its different sinus, its 
broadly elliptic vertical view, and its distinctly granulate membrane. 
The latter character as well as its form distinguishes it from C. 
Ralfsii r Breb. From C. pseudoy achy der mum Nordst. (Freshw. 
Alg. of New Zeal, and Austr., p. 53, tab. v. f. 20) — which it much 
resembles both in form and size as well as in vertical view — it also 
chiefly differs in its distinctly granulate membrane, which moreover 
distinguishes it from G. pjramidatum Breb., this latter being com- 
paratively longer and more angular in its front view, and also 
different in its lateral view as well as in its smaller size. 
C. exiguum Arch, in Micr. Journ., 1864, p. 178, t. 6, f. 32 and 33. 
Cooke Brit. Desm., p. 92, t. 43, f. 4. 
var. pressum var. n. Fig. 1. 
Yar. duplo minor, paullo angustior, apicibus levissime 
retusis. 
Long. 12 * 5-14 ’5 y ; lat. 5 ■ 8-6 * 5 y ; lat. isthm. 
3 * 5-4 *5 y\ crass. 5 y,. 
Hab. Elter Water, Lake District. 
C. prominulum Bacib., Nonnul. Desmid. Polon., p. 23, tab. ii. 
fig. 7. 
var. subundulatum var. n. Fig. 16. 
Var. semicellulis apicibus leve 4-undulatis, marginibus 
lateralibus superioribus leve biundulatis ; a vertice 
visae tumoribus medianis utrobique angustioribus, 
tumoribus prope apices majoribus et distantioribus 
de polis acutioribus. 
Long. 16-18 y ; lat. 17-19 y; lat. isthm. 8-9*5 y; 
crass. 13*5 y. 
Hab. Elter Water, Lake District. 
