I 



O'Meara — Report on the Irish Diatomacece. 417 



Navicula glohifera, N. S. Fresh water. 



Valve narrow, margin slightly constricted ; ends constricted and 

 broadly capitate. Strise extremely fine, close, convergent ; length 

 •0018, breadth -0003. (Plate 34, fig. 32.) 



This form is very similar to that described by Gregory as Pinnii- 

 laria globiceps, Q. J. M. S., 1856, p. 10, PI. i., fig. 34; but differs in 

 the following respects : in Gregory's form the valve is obviously ex- 

 panded in the middle ; in this it is linear, with the appearance of a 

 slight constriction in the middle ; the striae in this are much finer, and 

 reach the median line, instead of leaving a central stauroform free 

 band, as is the case with Pinnularia globiceps. 



Camolin, Co. "Wexford. 



Navicida rosfellifera, (Gregory). Marine or brackish water. 



Valve minute, narrow, linear ; narrowed towards the ends, which are 

 apiculate. Striae costate, convergent in the middle ; frustule on front 

 view constricted in the middle ; length of valve .0013, breadth "0003. 

 (Plate 34, fig. 33.) 



Pinnularia apiculata, Gregory, Q,. J. M. S., 1856, p. 41, PI. iv., 

 fig. 21. This form appears to be the same which Donkin describes as 

 Navicula apiculata, JDe Brebisson, and Pinnularia rostellata, Gregory, 

 Diat., of Clyde, p. 488, PL ix., fig. 20. See Donkin, N. H. Brit. 

 Diat., p. 56, PI. viii., fig. 6. Gregory himself evidently regarded the 

 forms as distinct ; and comparison of the two compels me to coincide 

 with that eminent observer. Navicula apiculata, De Brebisson, and 

 Pinnularia rostellata, Gregory, are obviously identical, and quite 

 different from the present, which is much smaller and narrower in 

 proportion ; the striae being very strong, and reaching the median line, 

 while in this other they leave a considerable blank space about the 

 central nodule ; the rostrate ends too in the latter are much produced, 

 while in this species they are very short. Gregory's specific term 

 apiculata having been appropriated by De Brebisson, ought to drop, 

 and the form so distinctly described by Gregory bear another desig- 

 nation, to avoid confusion. 



Lough Gill, Co. Kerry. Portmarnock, Co. Dublin. 



Navicula cancellata, (Donkin). Marine. 



Valve large, narrow, linear, with cuneate ends. Striae strongly 

 costate ; convergent in the middle, nearly parallel towards the ends ; 

 length -0036, breadth -0006. Frustule on front view slightly con- 

 stricted, the costae appearing in a broad band. (Plate 34, fig. 34.) 



Donkin, K. H. Brit. Diat., p. 55, PI. viii. fig. 4. Kavicula trun- 

 cata, Donkin, Q. J. M. S., 1861, p. 9, PI. i., fig. 4, and changed for 

 the present designation, the former name having been anticipated by 

 Kutzing. — Pinnularia truncata, Rab. PL Eur. Alg., sect, i., p. 217. 



Arran Islands ; Stomachs of Ascidians, Roundstone Bay ; Sto- 

 machs of Ascidians, Broadhaven Bray, Co. Galway, Malahide, Port- 

 marnock, Co. Dublin. 



