O’Mrara—Report on the Irish Diatomacee. 333 
state of things occurs, I have not found this view confirmed. So that 
probably Schizonema does not differ in this respect from the rest of 
the Navicule.’’—Untersuchungen tiber Bau und Entwicklung der Bac- 
illariaceen, p. 75. 
(+) Frustules with parallel stri. 
Schizonema crucigerum, (Wm. Sm.) Marine. 
- “Frond filiform; filaments implicate below, free above, much 
divided. Frustules crowded. Valves with a distinct stauros, lanceolate, 
acute’? (Wm. Smith) on side view ; on front view wider in the middle 
than at ends. Strie distinct, close, limear. (Pl. 29, fig. 17.) 
In Smith’s figure, the striz are described as slightly radiate, but 
in my specimens, I find them parallel. 
Wa em, - Vol m, p. 74., Pl. ly., fie. do4, and PY. Tyas, 
fig. 356. Ralfs, in Pritch., p. 928. Rab. Fl. Eur. sect. 1, p. 266. 
—Stauroneis crucigera, Heiberg, De Danske Diat., p. 88. 
Tacumshane, Co. Wexford. Malahide, Portmarnock, Salt-hill, 
Co. Dublin. Rostrevor, Co. Down. Lough Gill, Co. Kerry. 
Schizonema snuthii, (Agardh.) Marine. 
‘‘ Frond, filiform, robust, simple below, much divided, fasciculated 
and fastigiate above. Frustules in numerous closely set files. Valves 
elliptico-lanceolate, acute.”—Wm. Smith. To which I would add, strie, 
obvious, extending to median line. Front view of frustule regularly 
quadrangular. (Pl. 29, fig. 18.) 
Agardh. Conspectus, p. 18. Kitz. Bac., p. 114, T. xxvii., fig. 5. 
Warvom. o. Vol mp. 7), EL. tvit., fe. 662... Rab. Rl. Wur:, 
sect. 1, p. 269.—Micromega Smithu, Ralfs, in Pritch., p. 930. 
Howth, Salt Hill, Malahide, Co. Dublin. Seacoast, Co. Antrim. 
Schizonema divergens, (Wm. Sm.) Marine. 
‘Frond, simple below, sparingly divided, or by cohesion irregu- 
larly submembranous above; ultimate ramuli short, obtuse.”,—Wm. 
Smith. Valve, shorter and wider than the last, and more rounded at the 
ends. Stric fine, hnear, reaching the median line. 
Wm. sm., B,D. Volous p To; El lvu-, fie. 363. ‘Rab. FI Eur. 
sect. 1, p. 269.—Micromega divergens, Ralfs, in Pritch., p. 981. 
Besides the locality named by Wm. Smith, Larne Lough, where it 
was collected by Dr. Dickie, this species has been gathered by mysclf 
at Malahide and Salt-hill, Co. Dublin; and by Dr. David Moore, at 
Carrickfergus and Carnlough Bay, Co. Antrim. 
Schizonema mucosum, (Kiitz.) Marine. 
‘Frond filiform, gelatinous, simple below, by cohesion sub-mem- 
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