392 Proceediugs of the Royal Irish Academy. 



the middle, convergmg' at the attenuated extremities ; striae obviously 

 moniliform ; length, about -0056, breadth, about "0024. (Plate 33, 

 fig. 2.) 



This fonn was first described by "Wm. Smith, who doubtfully 

 considered it a sporangial variety of Xavicula elliptiea, B. D., Yol. i., 

 p. 48, PI. svii., fig. 152 a. Subsequently the same author regarded 

 it as identical with JSTavicula lyra, Ehr., E. D., Yol. ii., p. 93 ; but 

 judging by the figure which Kiitzing has given of the latter, there 

 can be little doubt that the forms are not altogether identical. Still, 

 so similar are they, that it seems desirable to represent them as 

 merely varieties. Schmidt, Atlas der Diat., T. ii. fig. 29. 



Stomachs of Aseiclians, Belfast Lough. Stomachs of Asciclians, 

 Ealkee, Co. Clare. Arran Islands; Stomachs of Ascidians, Eoundstone 

 Bay ; Stomachs of Ascidians, Broadhaven Bay, Co. Galway. Bally- 

 sodare, Co. Sligo. Bannow, Co. "Wexford. 



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



Yalve broadly elliptical ; marginal band of striae very broad ; 

 inner band of striae narrow ; intermediate space between the inner 

 and outer bands of stride narrow, converging, and anastomosing at the 

 ends ; striae verv close, radiate, minutely punctate ; length '0028, 

 breadth -0015. (Plate 33, fig. 3.) 



Grunow, Yerhand. der K. K.' Zool. Bot. Gesell., Band x., 1860, 

 15. 532, T. v., fig. 22. The author just named regards the form as 

 identical with J^avicula Lyra, Ehr., as described by Kiitzing, Bac, 

 p. 96, T. xxviii., fig. 55 ; but comparison of specimens of both will 

 convince the observer that the forms are not identical ; so distinct are 

 their details that the present form might almost be regarded as entitled 

 to a distinctive specific name. 



Arran Islands ; Stomachs of Ascidians, Broadhaven Bay ; Stomachs 

 of Asciclians, Eoundstone Bay, Co. Galway, 



Var. minor, (Grnnow). Marine. 



This variety resembles that last described, but difiers from it in 

 the following characters ; the form is much smaller, the ends are broacUy 

 rounded, and the lyrate space between the two bands of striae is much 

 more convex ; length -0015, breadth .C009. (Plate 33, fig. 4.) 



Grunow, Yerhancl. der K. K. Zool. Bot. Gesell., Band x., 1860, 

 p. 532, PL v., fig. 23. 



Stomachs of Ascidians, Eoundstone Bay ; Arran Islands, Co. 

 Galway. 



Var. fore ipata, (Greville). Marine. 



Yalve elliptical, oblong ; marginal and inner bands of strije sepa- 

 rated by a broad lyrate, blank space ; convergent at the ends ; striae, 

 minutely monilLform ; length about '0024, breadth about -0010. 



Greville, Q. J. M. S. 1859, p. 83, PI. vi., figs. 10, 11. EaLFs, in 

 Pritch., p. 897. Eab. Fl. Eur., Alg., sect, i., p." 178. Donkia, K H. 



