O'Meara — Report on the Irish Diatomacece. 387 



Navicula hennechji, (Win. Sm.) [Marine. 



Yalve broadly elliptical, ends not produced ; striae monilif orm ; 

 inner and outward bands of striae, narrower than in Navicula clavata, 

 but in other respects very similar ; length about "0030, breadth 

 about -0020. (Plate 32, fig. 24.) 



Wm. Sm., B. D., Vol. ii., p. 93. Gregory, Q. J. M. S. Trans., 

 1856, p. 40, PI. v., fig. 3. Ealfs, in Pritch., p. 898. Rab. Fl. Eur. 

 Alg. sect, i., p. 178. Donkin, X. H. Brit. Diat., p. 11, PL ii., fig. 3. 

 Schmidt, Atlas der Diat., T. iii., figs. 17, 18. 



Stomachs of Ascidians, Belfast Lough, Co. Antrim. Stomachs of 

 Ascidians, Roundstone Bay ; stomachs of Ascidians, Broadliaven Bay, 

 Arran Islands, Co. Galway. 



Navicula nelulosa, (Gregory). Marine. 



Valves in outward form similar to those of Ifavicula hennedyi, but 

 narrower ; the space intervening between the outer and inner bands 

 of striae obscurely marked with very fine parallel lines of puncta, 

 which do not extend throughout; length about "0042, breadth about 

 -0020. (Plate 32, fig. 25.) 



Gregory, Diat. of Clyde, p. 480, PI. ix., fig. 8. Ealfs, in Pritch., 

 p. 898. Bab. PL Eur. Alg. sect. L, p. 179. Donkin, N. H. Brit. 

 Diat., p. 11, PL ii., fig. 2. Schmidt, Atlas der Diat., T. iii., fig. 14. 

 The clouded appearance of the space intei'vening between the inner 

 and outer bands of striae, as represented in the figures of Gregory and 

 Donkin, is found with good illumination to arise from the fine punctate 

 striae above referred to. 



Stomachs of Ascidians, Boundstone Bay, Arran Islands, Co. 

 Galway. 



Var. suborlicularis, (O'Meara). Marine. 



Valve shorter and relatively broader than that of the typical 

 species ; marginal band of striae relatively broader ; that next the 

 median line relatively narrower ; intermediate space between the inner 

 and outer bands of strife narrow, and occupied by irregularly disposed 

 puncta; length -0024, breadth -0014. (Plate 32, fig. 26.) 



Arran Islands, Stomachs of Ascidians, Boundstone Bay, Co. 

 Galway. 



JSfavicula pr<Btexta, (Ehr.) Marine. 



Valve broadly elliptical ; marginal band of strife broad, distinctly 

 moniliform ; median bands of striae broad, distinctly moniliform ; inter- 

 mediate space between the outer and inner bands of striae ornamented 

 with iiTegularly arranged large, round puncta ; free unstriate space 

 between the median line and the inner margins of the inner band of 

 striae expanding in the middle, with a narrow staurofonn band ; length 

 about -0040, breadth about -0025. (Plate 32, fig. 27.) 



Ehi'enberg, in Proceechngs of Berlin Acad., 1840, p. 20. Kiitz. 



