366 Proceedings of the Royal Irish Academy. 



or XoTilla ; for whicli reason tliis species ouglit to be transfen-ed to a 

 new genus, distingnisliecl from Xavieula by the cuneate front view. 

 The side yiew "vras suifieiently confonnable "with Grunow's description." 

 The cuneate appearance of the fi'ont view just referred to, I am 

 inclined to think, was casual, arising from the separation of the 

 valves at one end, while at the other end they retained their 

 normal position. In the specimen I was able to observe on the 

 front view, there was but a single valve, which did not exhibit any 

 tendency to a cuneate outline. 



Stomachsof Ascidians, Eoundstone Bay, Arran Islands. Co. Galway. 

 Bantry Bay, Co. Cork. 



Navicula grilndleriana, 'E. S. Marine. 



Yalve linear elliptical ; somewhat cuneate at the ends ; interme- 

 diate free s]Dace naiTow, except in the middle, where it expands into 

 a broad, subquach-angular area. Striae linear, slightly radiate ; longi- 

 tudinal sulcus marginal. (PI. 31, fig. 25.) 



This form strongly resembles a Xavicula figui'ed by Schmidt, Atlas, 

 T. vi,, figs. 31 and 32 ; and by this author attiibuted to Griindler. 

 It differs however, inasmuch as the striae in the latter are described 

 as punctate ; in the present case they are linear. The free area 

 around the central nodule in this form is much larger than in that 

 figured by Schmidt. The strong similarity has suggested the specific 

 name. 



The present form upon first view might be easily confounded with 

 jSTavicula macula, Greg., fi'om which it may be discerned by the 

 fact that the ends in the latter ai-e contracted and rounded ; in this 

 they are cuneate. The striae, too, in this are very much coarser and 

 more distant than in Xav. macula. 



Stomachs of Ascidians, Broadhaven Bay, Co. Galway. 



(e) LimoscB. 



Longitudinal sulci more numerous than in the last, and generally more 

 highly developed ; intermediate free space narrow. 



Navicula iridis, (Ehr.) Freshwater. 



Yalve lineal', elliptical, rounded off at the ends. Striae fine, Hnear, 

 parallel ; intermediate fi'ee space narrow towards the ends, expanded 

 in the middle ; length from -0046 to -0072, breadth fi'om -0010 

 to -0016. Longitudinal striae distinct at the margin. (PL 31, 

 fig. 26.) 



Kiitz. Bac, p. 92, T. xxviii., fig. 42. Ealfs, in Pritch., p. 907. 

 Eab. Fl. Eui\ Alg., sect, i., p. 171. Donkin, K. H. Brit. Diat., 

 p. 30, PI. v., fig. 6.— Navicula firma, Wm. Sm., B. D., Yol. i., p. 48,. 



