O'Meara — Report on the Irish Diatomacece. 405 



Var. intermedia, (0'3Ieara). Marine. 



Yalve considei'ably smaller than that of the typical form ; the 

 lobes are more expanded ; the ends of the costse on the inner edge of 

 the compartments on either side of the median one are longer, the 

 ridge seeming to he in this case wider, and not so mnch elevated. 



This is, perhaps, identical with Xavicula crahro, Grunow, Yer- 

 hand. der K. K. Zool. Bot. Gesell., Band x., 1860, p. 524, T. v., 

 fig. 21, and with jS'avicnla nitida, Gregory, Q. J. M. S., 1856, p. 44, 

 PI. v., fig. 12. 



Broadhaven Bay. Eoundstone Bay. 



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



Yalve very much smaller than the preceding variety, not so much 

 constricted, the ends of the stride appearing on the inner edge of the 

 compartments on either side of the median one being of the same 

 breadth, or nearly so, as that of the costas of the marginal band of strias, 

 which are very narrow. (Plate 33, fig. 34.) 



iSTavicula denticulata, O'Meara, Q. J. M. S., 1867, p. 115, PI. v., 

 fig. 2. In the description at first given of this form it would appear as 

 if the space between the two bands of costse were unstriate ; but upon 

 more close examination, with better illumination than I then possessed, 

 I have satisfied myself that the costse pervade the interspace. They 

 are indeed very indistinct, but still traceable. 



Arran Islands ; Stomachs of Ascidians, Broadhaven Bay ; Stomachs 

 of Ascidians, Eoundstone Bay, Co. Galway. 



JVavicuIa pfit%eriana, K". S. Marine. 



Yalve small, slightly constricted ; median compartment very nar- 

 row, lanceolate ; compartments at either side become wider in. middle 

 than at ends ; striate ; marginal striate band relatively wide ; striae 

 linear, close, convergent in the middle, thence finer, and nearly paral- 

 lel ; length -0017, breadth -0005; breadth at constriction -0004. 

 (Plate 33, fig. 35.) 



This form was a considerable time ago exliibited by me among 

 other interesting species collected by Mr. Mozely, H. M. S. Challenger, 

 on the coast of Patagonia. It is identical with a specimen fi-om Yal- 

 paraiso, figured as JSTavicula divergens by Schmidt, Atlas der Diat., 

 T. xii., fig. 53; but as my designation has the priority of publication, 

 it has a right to stand. 



Stomachs of Ascidians, coAst of Co. Clare, 



JVavicuIa vichersii, ]Sr. S. Marine. 



Yalve very large, deeply constricted ; median compartment linear, 

 wide ; compartments on either side wide, unstriate, bilunate on the 

 outer margin ; marginal striate band narrow in the middle, widening 

 towards the broadest part of the heart-shaped lobes, and thence decreas- 

 ing in width towards the rounded ends ; striae costate, nearly parallel 



