384 Proceedings of the Royal Irish Academy. 



Var.'riwmlica, (0']Meara). Marine. 



Yalve like that of the typical form in general structure, but dif- 

 fering in its distinctly rhombic outline, as Tvell as in the rhombic form 

 of the inner band of strise. 



A form which seems to me to be identical with this is described bj 

 Schmidt, Atlas der Diat., T. Tii., fig. 18. 



An-an Islands, Co. Galway. 



JSfavicida coUisiana, X. S. ^Marine. 



Yalve broadly elliptical. jS'early linear at the margin, with broadly 

 rounded ends. Intermediate space wide, oblong, elliptical. Stri^ cos- 

 tate. Marginal striate band wide, striae distinctly moniliform, nearly 

 parallel in the middle ; more and more radiate towards the ends ; 

 length -0026, breadth -0016. (Plate 32, fig. 19.) 



This foiTu is distinguished fi-om jSTavicula fusca, and Xayicula 

 smithii, which in other respects it strongly resembles, by the broad 

 oblong elliptical outline of the inner striate band, and more specially 

 by the fact that the strife in this portion of the valve are distinctly 

 costate, while in the others they are moniliform. It was first ex- 

 hibited by me at a meeting of the Dublin Microscopical Club, some 

 years since, at the house of the late Sui-geon Maurice Collis. 



Stomachs of Ascidians, E-oundstone Bay, Arran Islands, Co.. 

 Galway. Xilcool, Co. "Wicklow. 



N'avicida cestiva, (Donldn). Marine. 



Yalve linear, elliptical ; strife fine, obscurely moniliform, parallel in 

 the middle, slightly radiate towards the ends ; inner striate band narrow, 

 elliptical ; length about "0022 ; breadth about -0010. The distinctive 

 character of this species is the fineness of the striae. (Plate 32, fig. 20.) 



Donkin, Q. J. M. S. Trans., 1858, p. 32, PL iii., fig. 18; and 

 N. H. Brit. Diat., p. 6, Pl.i., fig. 3. Donkin's figures represent the spe- 

 cies as much larger than mv specimens would lead me to regard it. 

 EaKs, inPritch., p. 899. Eab. PL Eur. Alg., sect, i., p. 184. 



Arran Islands, Stomachs of Ascidians, Broadhaven Bay, Co. Gal- 

 way. 



Navicida elliptiea, (Kiitz.) Presh water. 



Yalve elliptical ; strias of the marginal band distinctly moniliform, 

 converging in the middle, radiate towards the ends ; inner striate band 

 very narrow ; fi'ee space about the median line greatly expanded, 

 forming a rounded rhombic outline ; median line strongly developed • 

 length about -0020, breadth about -0011. (Plate 32, fig.' 21.) 



Kutz. Bac, p. 98, T. xxx., fis;. 55. Y"m Sm., B. D., Yol. ii., 

 p. 92. Ealfs, in Pritch., p. 899. Eab. PL Eur. Alg., sect, i., p. 179. 



