O'Meara — Report on the Irish Diatomacece. 369 



Navicula imdosa, (Ekr.) Fresh "U^ater. 



Valve broadly elliptical, slightly triundiilate ; apices produced, 

 very narroTv, and slightly capitate ; longitudinal strias distinct ; trans- 

 verse striae obscui'e ; length -0016, breadth -0006. (Plate 31, fig. 32.) 



Kiitz. Bac, p. 101, T. xxviii., fig. 83. Rab. Siissw. Diat., p. 41, 

 T. vi., fig. 56. 



Eiver Erne, near Crossdoney, Co. Cavan. 



Navicida esox, (Ehr.) Habit, doubtful. 



Yalve lanceolate, "with an angular expansion in the middle; margin 

 slightly tiiundulate ; ends cuneate ; strife distinct, linear, punctate, 

 nearly parallel in the middle, slightly radiate and closer towards the 

 ends ; median line strongly developed ; terminal nodules at some dis- 

 tance from the ends; length '0034, breadth '0010. (Plate 31, 

 fig. 33.) 



Kiitz. Bac, p. 94, T. xxviii., fig. 53, who regards the species as 

 identical with Pinnularia esox, Ehr. Ralfs, in Pritch., p. 896, PI. 

 xii., fig. 43. The description in this case is tolerably accurate, but 

 the figure is incorrect. — Pinnularia esox, Eab Siissw. Diat., p. 45, 

 T. vi., fig. 7. This figiu-e does not at all represent the peculiarities 

 of the species. 



It is doubtful whether this is a fresh- water or marine form. 

 Eabenhorst includes it among the former ; the only gathering in which 

 I found it was marine, yet containing some fresh water forms. 



Mud from salt water, coast of Clare, supplied by Doctor Sullivan, 

 President Queen's College, Cork. 



Nmicula trochus, (Ehr.) Fresh water. 



Yalve inflated in the middle, gi-eatly contracted towards the ends, 

 which are slightly capitate ; transverse strise indistinct ; longitudinal 

 striae distinct ; intermediate free space narrow, except in the middle, 

 where it is expanded. (Plate 31, fig. 34.) 



Kiitz. Bac, p. 99, T. iii., fig. 59. Ptalfs, in Pritch., p. 899.— 

 J^'avicula follis, Donkin, jST. H. Brit. Diat., p. 44, PI. vi., fig. 15. 

 There is considerable difficulty as to the synonymy of this species. 

 Donkin considers it identical with Xavicula follis, Ehr., Xavicula crux, 

 Ehr., andXavicula inflata, Kiitz. Supposing the figures of the last named 

 asdelineatedbyKutzing(Bac.,T.iii., fig. 36), andbyEabenhorst(Siissw. 

 Diat., p. 41, T. v., fig. 10), to be correct, and that the former author 

 was correct in supposing ISTavicula inflata to be identical with Xavicula 

 follis, Ehr., I cannot think that the latter is likely to be identical 

 with Xavicula trochus. Kiitzing has figured Xavicula trochus so accu- 

 rately, that it is easily recognisable ; it is identical with that under 

 consideration, and also, as it appears to me, with that named jSTavicula 

 follis, by Donkin. 



Lough Mourne deposit. 



